Video Surveillance of Nesting Birds 9780520954090

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VIDEO SURVEILLANCE of NESTING BIRDS

STUDIES IN AVIAN BIOLOGY A Publication of the Cooper Ornithological Society WWW.UCPRESS.EDU/GO/SAB

Studies in Avian Biology is a series of works published by the Cooper Ornithological Society since 1978. Volumes in the series address current topics in ornithology and can be organized as monographs or multi-authored collections of chapters. Authors are invited to contact the series editor to discuss project proposals and guidelines for preparation of manuscripts.

Series Editor Brett K. Sandercock, Kansas State University Editorial Board Frank R. Moore, University of Southern Mississippi John T. Rotenberry, University of California at Riverside Steven R. Beissinger, University of California at Berkeley Katie M. Dugger, Oregon State University Amanda D. Rodewald, Ohio State University Jeffrey F. Kelly, University of Oklahoma Science Publisher Charles R. Crumly, University of California Press See complete series list on page 223.

VIDEO SURVEILLANCE of NESTING BIRDS Christine A. Ribic, Frank R. Thompson III, and Pamela J. Pietz, Editors Studies in Avian Biology No. 43

A PUBLICATION OF THE COOPER ORNITHOLOGICAL SOCIETY

University of California Press Berkeley

Los Angeles

London

University of California Press, one of the most distinguished university presses in the United States, enriches lives around the world by advancing scholarship in the humanities, social sciences, and natural sciences. Its activities are supported by the UC Press Foundation and by philanthropic contributions from individuals and institutions. For more information, visit www.ucpress.edu. Studies in Avian Biology No. 43 University of California Press Berkeley and Los Angeles, California University of California Press, Ltd. London, England © 2012 by the Cooper Ornithological Society Library of Congress Cataloging-in-Publication Data Ribic, Christine A. Video surveillance of nesting birds / Christine A. Ribic, Frank R. Thompson III, and Pamela J. Pietz. p. cm. — (Studies in avian biology ; No. 43) Includes bibliographical references and index. ISBN 978-0-520-27313-9 (cloth : alk. paper) 1. Bird populations. 2. Birds—Monitoring—Methodology. 3. Birds—Nests. 4. Birds—Behavior. 5. Ornithology—Methodology. 6. Ornithology—Technique. I. Thompson, Frank R. (Frank Richard) II. Pietz, Pamela J. III. Title. QL677.4.R53 2012

598.072’32—dc23 2011044824

19 18 17 16 15 14 13 12 10 9 8 7 6 5 4 3 2 1 The paper used in this publication meets the minimum requirements of ANSI/NISO Z39.48-1992 (R 2002) (Permanence of Paper). Cover photograph: Field Sparrow chicks, three days old. Photo by Carolyn M. Schmitz.

PERMISSION TO COPY The Cooper Ornithological Society hereby grants permission to copy chapters (in whole or in part) appearing in Studies in Avian Biology for personal use, or educational use within one’s home institution, without payment, provided that the copied material bears the statement “© 2012 The Cooper Ornithological Society” and the full citation, including names of all authors. Authors may post copies of their chapters on their personal or institutional website, except that whole issues of Studies in Avian Biology may not be posted on websites. Any use not specifically granted here, and any use of Studies in Avian Biology articles or portions thereof for advertising, republication, or commercial uses, requires prior consent from the series editor.

CONTENTS

Contributors / vii Preface / xi Foreword / xiii

Part I • Synthesis/Overview 1 • KNOWLEDGE GAINED FROM VIDEO-MONITORING GRASSLAND PASSERINE NESTS / 3

Pamela J. Pietz, Diane A. Granfors, and Christine A. Ribic 2 • CONSERVATION IMPLICATIONS WHEN THE NEST PREDATORS ARE KNOWN / 23

Frank R. Thompson III, and Christine A. Ribic 3 • GAMEBIRDS AND NEST CAMERAS: PRESENT AND FUTURE / 35

6 • SPRAGUE’S PIPIT INCUBATION BEHAVIOR / 67

Stephen K. Davis and Teslin G. Holmes 7 • PATTERNS OF INCUBATION BEHAVIOR IN NORTHERN BOBWHITES / 77

Jonathan S. Burnam, Gretchen Turner, Susan N. Ellis-Felege, William E. Palmer, D. Clay Sisson, and John P. Carroll 8 • THE INFLUENCE OF WEATHER ON SHOREBIRD INCUBATION / 89

Paul A. Smith, Sarah A. Dauncey, H. Grant Gilchrist, and Mark R. Forbes 9 • NOCTURNAL ACTIVITY OF NESTING SHRUBLAND AND GRASSLAND PASSERINES / 105

Christy M. Slay, Kevin S. Ellison, Christine A. Ribic, Kimberly G. Smith, and Carolyn M. Schmitz

Susan N. Ellis-Felege and John P. Carroll

Part II • Breeding Behavior 4 • HATCHING AND FLEDGING TIMES FROM GRASSLAND PASSERINE NESTS / 47

Pamela J. Pietz, Diane A. Granfors, and Todd A. Grant 5 • ATTENDANCE PATTERNS AND SURVIVAL OF WESTERN MEADOWLARK NESTS / 61

Larkin A. Powell, Matthew D. Giovanni, Scott Groepper, Mitchell L. Reineke, and Walter H. Schacht

Part III • Behavioral Responses to Predation/Predator Identification 10 • BIRD PRODUCTIVITY AND NEST PREDATION IN AGRICULTURAL GRASSLANDS / 119

Christine A. Ribic, Michael J. Guzy, Travis J. Anderson, David W. Sample, and Jamie L. Nack 11 • PREDATORY IDENTITY CAN EXPLAIN NEST PREDATION PATTERNS / 135

Jennifer L. Reidy and Frank R. Thompson III

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12 • NEST DEFENSE: GRASSLAND BIRD RESPONSES TO SNAKES / 149

Kevin S. Ellison and Christine A. Ribic 13 • PARTIAL DEPREDATIONS ON NORTHERN BOBWHITE NESTS / 161

Part IV • Technology 15 • DEVELOPMENT OF CAMERA TECHNOLOGY FOR MONITORING NESTS / 185

W. Andrew Cox, M. Shane Pruett, Thomas J. Benson, Scott J. Chiavacci, and Frank R. Thompson III

Susan N. Ellis-Felege, Anne Miller, Jonathan S. Burnam, Shane D. Wellendorf, D. Clay Sisson, William E. Palmer, and John P. Carroll

Appendix / 199

14 • IDENTIFICATION OF SPRAGUE’S PIPIT NEST PREDATORS / 173

Index / 211 Complete Series List / 223

Stephen K. Davis, Stephanie L. Jones, Kimberly M. Dohms, and Teslin G. Holmes

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CONTRIBUTORS

TRAVIS J . ANDERSON

W . ANDREW COX

Department of Forest and Wildlife Ecology University of Wisconsin 1630 Linden Drive Madison, WI 53706, USA (Current address: Wisconsin Department of Natural Resources Wildlife Management Dodgeville, WI 53533, USA, [email protected])

Department of Fisheries and Wildlife Sciences 302 ABNR University of Missouri Columbia, MO 65211, USA [email protected]

THOMAS J . BENSON

Illinois Natural History Survey Institute of Natural Resource Sustainability University of Illinois 1816 South Oak Street Champaign, IL 61820, USA [email protected] JONATHAN S . BURNAM

Warnell School of Forestry and Natural Resources University of Georgia Athens, GA 30602, USA [email protected] JOHN P . CARROLL

Warnell School of Forestry and Natural Resources The University of Georgia Athens, GA 30602, USA [email protected] SCOTT J . CHIAVACCI

Department of Biological Sciences P.O. Box 599 Arkansas State University State University, AR 72467, USA [email protected]

SARAH A . DAUNCEY

Golder Associates Ltd. 32 Steacie Drive Kanata, ON, K2K 2A9, Canada (Current Address: Smith and Associates Ecological Research Ltd. 772–7th Concession South Pakenham, ON, K0A 2X0, Canada, [email protected]) STEPHEN K . DAVIS

Department of Biology University of Regina 3737 Wascana Parkway Regina, SK, S4S 0A2, Canada and Environment Canada/Canadian Wildlife Service 300 – 2365 Albert Street Regina, SK, S4P 2K1, Canada [email protected] KIMBERLY M . DOHMS

Department of Biology University of Regina 3737 Wascana Parkway Regina, SK, S4S 0A2, Canada (Current address: Biological Sciences University of Lethbridge 4401 University Way Lethbridge, AB, T1K 3M4, Canada, [email protected]) vii

SUSAN N . ELLIS - FELEGE

Warnell School of Forestry and Natural Resources The University of Georgia Athens, GA 30602, USA (Current address: Department of Biology University of North Dakota 10 Cornell Street, Stop 9019 Grand Forks, ND 58202, USA, [email protected])

Department of Agronomy and Horticulture 279 Plant Science Hall University of Nebraska–Lincoln Lincoln, NE 68503-0915, USA (Current address: The Peregrine Fund 5668 West Flying Hawk Lane Boise, ID 83709, USA, [email protected]) DIANE A . GRANFORS

KEVIN S . ELLISON

Department of Forest and Wildlife Ecology University of Wisconsin 1630 Linden Drive Madison, WI 53706, USA (Current address: Wildlife Conservation Society 301 N. Willson Avenue Bozeman, MT 59715, USA, [email protected]) JOHN FAABORG

University of Missouri Columbia, Missouri Division of Biological Sciences 224 Tucker Hall University of Missouri Columbia, MO 65211, USA [email protected] MARK R . FORBES

Department of Biology Carleton University 1125 Colonel By Drive Ottawa, ON, K1S 5B6, Canada [email protected] H . GRANT GILCHRIST

Environment Canada Science and Technology Branch 1125 Colonel By Drive Ottawa, ON, K1A 0H3, Canada [email protected] MATTHEW D . GIOVANNI

School of Natural Resources 3310 Holdrege Street University of Nebraska–Lincoln Lincoln, NE 68583-0974, USA and

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U.S. Fish and Wildlife Service Habitat and Population Evaluation Team 18965 County Highway 82 Fergus Fall, MN 56537, USA (Current address: U.S. Fish and Wildlife Service 1011 East Tudor Road Anchorage, AK 99503, USA, [email protected]) TODD A . GRANT

U.S. Fish and Wildlife Service Souris River Basin National Wildlife Refuge Complex Upham, ND 58789, USA [email protected] SCOTT GROEPER

School of Natural Resources 3310 Holdrege Street University of Nebraska–Lincoln Lincoln, NE 68583-0974, USA [email protected] MICHAEL J . GUZY

Department of Forest and Wildlife Ecology University of Wisconsin 1630 Linden Drive Madison, WI 53706, USA [email protected] TESLIN G . HOLMES

Department of Biology University of Regina 3737 Wascana Parkway Regina, SK, S4S 0A2, Canada (Current address: Department of Biological Sciences University of Alberta Biological Sciences Building CW 405, Edmonton, AB, T6G 2E9, Canada, [email protected])

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Ribic, Thompson, and Pietz

STEPHANIE L . JONES

MITCHELL L . REINEKE

U.S. Fish and Wildlife Service P.O. Box 25486 DFC Denver, CO 80225, USA [email protected]

School of Natural Resources 3310 Holdrege Street University of Nebraska–Lincoln Lincoln, NE 68583-0974, USA [email protected]

ANNE MILLER

Warnell School of Forestry and Natural Resources University of Georgia Athens, GA 30602, USA [email protected] JAMIE L . NACK

Department of Forest and Wildlife Ecology University of Wisconsin 1630 Linden Drive Madison, WI 53706, USA [email protected] WILLIAM E . PALMER

Tall Timbers Research Station and Land Conservancy, Inc. 13093 Henry Beadel Drive Tallahassee, FL 32312, USA [email protected] PAMELA J . PIETZ

U.S. Geological Survey Northern Prairie Wildlife Research Center 8711 37th Street Southeast Jamestown, ND 58401, USA [email protected] LARKIN A . POWELL

School of Natural Resources 3310 Holdrege Street University of Nebraska–Lincoln Lincoln, NE 68583-0974, USA [email protected] M . SHANE PRUETT

Avian Ecology Lab Archbold Biological Station 123 Main Drive Venus, FL 33960, USA [email protected] JENNIFER L . REIDY

302 Natural Resources Building University of Missouri Columbia, MO 65211, USA [email protected]

CHRISTINE A . RIBIC

U.S. Geological Survey Wisconsin Cooperative Wildlife Research Unit Department of Forest and Wildlife Ecology 204 Russell Labs 1630 Linden Drive Madison, WI 53706, USA [email protected] DAVID W . SAMPLE

Wisconsin Department of Natural Resources 2801 Progress Road Madison, WI 53716, USA [email protected] WALTER H . SCHACHT

Department of Agronomy and Horticulture 279 Plant Science Hall University of Nebraska–Lincoln Lincoln, NE 68503-0915, USA [email protected] CAROLYN M . SCHMITZ

Department of Forest and Wildlife Ecology University of Wisconsin 1630 Linden Drive Madison, WI 53706, USA [email protected] D . CLAY SISSON

Tall Timbers Research Station and Land Conservancy, Inc. 13093 Henry Beadel Drive Tallahassee, FL 32312, USA [email protected] CHRISTY M . SLAY

Department of Biological Sciences University of Arkansas Fayetteville, AR 72701, USA (Current address: The Sustainability Consortium 534 W. Research Boulevard University of Arkansas Fayetteville, AR 72701, USA, [email protected])

CONTRIBUTORS

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KIMBERLY G . SMITH

GRETCHEN TURNER

Department of Biological Sciences University of Arkansas Fayetteville, AR 72701, USA [email protected]

Warnell School of Forestry and Natural Resources University of Georgia Athens, GA 30602, USA [email protected]

PAUL A . SMITH

SHANE D . WELLENDORF

Department of Biology Carleton University 1125 Colonel By Drive Ottawa, ON, K1S 5B6, Canada (Current Address: Smith and Associates Ecological Research Ltd. 772–7th Concession South Pakenham, ON, K0A 2X0, Canada, [email protected])

Tall Timbers Research Station and Land Conservancy, Inc. 13093 Henry Beadel Drive Tallahassee, FL 32312, USA [email protected]

FRANK R . THOMPSON III

USDA Forest Service Northern Research Station 202 Natural Resources Building University of Missouri Columbia, MO 65211, USA [email protected]

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PREFACE

Concern about declining populations of bird species that breed in North America’s grasslands and other habitats has spurred extensive research on factors that may affect their reproductive success. Critical to this endeavor is an understanding of factors that affect nest survival and productivity. To address this need, in the mid-1990s, researchers began adapting miniature video cameras and recording equipment to create surveillance systems suitable for monitoring activities at cryptic bird nests. Since then, the range of applications for these camera systems has grown dramatically, and these systems have been used widely to study a variety of avian taxa in many different ecosystems. These camera studies have vastly expanded our knowledge of nest predation (typically the leading proximate cause of nest failure) and nesting biology for many bird species. To highlight the accumulated and growing information from video surveillance of bird nests, we convened a Coordinated General Session at the 2008 joint meeting of the American Ornithologists’ Union, the Cooper Ornithological Society, and the Society of Canadian Ornithologists (4–9 August; Portland, Oregon). This volume is an outgrowth of that session. Most papers in this volume are based on presentations given in the general session, but others were specially invited for this volume to illustrate additional types of information that can be obtained using video surveillance at nests.

This collection of papers provides (1) useful information on the applications and limitations of nest cameras in research; (2) examples of analyses, interpretation, and application of camera data to address a variety of research and management questions; and (3) a source of information obtained thus far on numerous species and subjects. These papers also illustrate how knowledge about activities at nests has furthered our understanding of avian ecology. This progress reflects, in part, the use of video data to corroborate or refute assumptions in the literature that have long been accepted but have been poorly or inadequately tested. As Margaret Morse Nice advised more than half a century ago (Wilson Bulletin 65:81–93), “we must demand the evidence” and not accept published accounts without scrutiny. We thank Carl D. Marti (now deceased, former Series Editor of Studies in Avian Biology) for inviting us to develop this volume, and Brett K. Sandercock (current Series Editor) for guiding us through the publication process. We thank all the volume contributors for their diligence and enthusiastic involvement in this effort and for their patience and perseverance during the lengthy period required to bring this volume to press. We also appreciate the time and expertise of the many reviewers who substantially improved each chapter of this volume. Finally, we thank Lawrence D. Igl, who recognized the value of this

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volume’s subject years ago, and suggested that we organize the Coordinated General Session on which this volume was based. He also provided information on potential contributors, supplied an abundance of pertinent literature, and provided insightful editing at every stage of this

project—from the proposal for the 2008 general session to several drafts of papers in this volume. CHRISTINE A . RIBIC USGS Wisconsin Cooperative Wildlife Research Unit Madison, Wisconsin FRANK R . THOMPSON III USDA Forest Service Northern Research Station Columbia, Missouri PAMELA J . PIETZ USGS Northern Prairie Wildlife Research Center Jamestown, North Dakota

4 April 2011

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FOREWORD

It is amazing the extent to which technological advances have changed our everyday lives. Just 20 years ago, we were cool walking around the house using a cordless telephone. As almost any old Seinfeld rerun on TV shows, those early cordless phones were huge, often with a retractable antenna; seeing them today is worth a laugh that was not written into the script. Most of us now use pocket-sized cellular phones, which also can function as cameras and message boards, and the current rage is smallish phones that virtually double as computers, so that one can get e-mail, send messages, search the web, or do virtually anything one can do on a computer with a hand-held device. There is even a TV commercial that plays on the question of whether a small electronic device is a phone or a computer, which tells us a great deal about miniaturization of computers too. Technological discoveries have also been important to the advancement of many historically non-technological areas of science such as fieldwork. This symposium volume deals with the use of video cameras in studies of nesting birds. Technological advances in the miniaturization of video cameras allow us to use hidden cameras at sites such as nests to see what is really happening. Although moving pictures of birds at nests have been around for a hundred years, these usually involved ponderous pieces of equipment that could only be run for short periods of time. New advances allow us to hide tiny video cameras near

nests or other sites, to have cameras that take pictures slowly enough that they can watch a site for long periods of time, to use infrared cameras so that they work through the night, and to use cameras that can be built cheaply enough that a graduate student can have adequate sample sizes to conduct good scientific experiments. We have even developed lightweight batteries and digital recorders, so the days where technicians had to haul 50-pound car batteries and videocassette recorders up and down mountain slopes may be over (if the budget can deal with the cost). Before we review briefly the details of what is included in this book, we need to remind ourselves how little we knew about avian ecology just 20 years ago, and how technological advances such as tiny video cameras have helped us advance our knowledge of the demography and behavior of birds. I consider 1989 an important turning point in modern avian ecology and conservation; perhaps it was even the beginning of modern bird conservation. Several papers had been written suggesting that birds were declining rapidly, and the birds suffering the most were those that traveled long distances between their temperate breeding grounds and their tropical or subtropical wintering sites. Short-distance migrants or permanent residents did not seem to be showing similar declines. An international meeting run by Manomet Bird Observatory got a large number of people who study these species together to understand what was going on,

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recognizing the fact that these long-distance migrants were distinctive because they spent several months on a breeding site, several months on a wintering site, and several months in transit between these two locations. Loss or degradation of habitat in any of these locations could prove to limit populations and cause declines. It quickly became apparent that we needed good data on nesting success of temperate breeding birds to explain the declines that were suggested by monitoring data. There were relatively few studies looking at migratory songbird nesting success, and most of those were what we called fragmentation studies. The development of the field of landscape ecology in the 1990s changed how we talked about these relationships between habitat area and bird distribution, but they did not change the general patterns. By the mid-1990s we knew that in most of the world highly fragmented landscapes (large areas where the only native vegetation occurs in small pieces) were horrible places for a bird to try and raise a family, while landscapes with little disturbance and mostly native habitat had higher nesting success. In general, we argued that landscapes with lots of edge and plenty of matrix supported nasty creatures such as crows, jays, and raccoons that entered the edge of the habitat remnants and destroyed most of the nests of the migratory birds. With enough fragmentation across a landscape, one could easily understand region-wide declines in migratory bird populations. Similar studies with gamebirds, especially waterfowl, suggested similar relationships among nest predation, predators, and landscapes. While most of these patterns are real and probably will remain part of conservation knowledge into the future, what we were doing in those early days was still pretty primitive. Yes, we could find and monitor nests in an attempt to figure out what nest success rates really were. Good guidelines for doing this were developed, such that most researchers were approaching nest monitoring in the same manner. Once given a data set for a nest, modelers developed better means of analysis, because it is not as easy as just finding a nest one day and seeing if it is empty somewhere down the line. Instead, it was important to figure out how old the nest was, when the young should fledge, and, ideally, to try and find the fledged family to verify success. But that was hard to do, and even hard to model.

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When a nest was lost to predation—and even in the best circumstances usually about half of the nests are lost—the researchers wanted to know which predator caused the loss. Some leave no clues, while others might. Researchers developed criteria on how to evaluate a depredated nest to predict the predator, although these criteria were rather vague and did not always work. A whole science that used artificial nests to try to track predation rates was developed, and many of these studies would use both a real egg and a plasticine egg in an attempt to get clues as to the nest predator from bill or teeth marks left in the plastic egg. While these artificial nest studies were attractive because of the sample sizes possible and the information from the plasticine egg, they soon were shown to be unrealistic measures of what was really going on, and many researchers suggested such artificial nest studies had no value, even with regard to the predator involved, which might not be a predator that would attack a real nest. Our concern was heightened when the first studies using video cameras showed that the actual nest predators were often not what we expected, and that predators could often remove young without damaging the nest. Camera studies made us totally rethink our assumptions about nest predation and nest predators. This volume presents a state-of-the-art look at the use of video camera technology in the study of bird nesting behavior. It begins with some synthesis/overview chapters, followed by a section on general breeding behavior and a section that focuses on nest predation. It ends with a chapter that describes the development of the technology of these video cameras and how one can put them together rather inexpensively. Chapters tend to be regionally focused, but these regions range from Florida to the Canadian Arctic, so the results of these studies are probably relevant to anyone doing temperate studies of nesting birds. The synthesis section begins with a look at all of the knowledge that can be gained from cameras when studying grassland birds (Chapter 1). It is quite obvious why cameras are valuable in grasslands, because in most cases these nests just cannot be seen from any distance. Cameras fix that, and allow us a tremendous look at a variety of nesting behaviors within this group of birds. Chapter 2 focuses on what we do with the sort of data that cameras allow us to gather. What are the implications for managers when we know the NO. 43

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actual predators at work? This section ends with a look at the role of cameras in studies of gamebirds (Chapter 3). Although much of the impetus for using cameras at nests was driven by the desire for knowledge about predation, the truth is that this technology allows tremendous insights into other aspects of avian nesting behavior. Cameras allow us to observe the timing of hatch and fledging in grassland birds of the upper Midwest (Chapter 4) and the nest attendance patterns of meadowlarks in Nebraska (Chapter 5). We learn about the details of incubation behavior in Sprague’s Pipits on the Canadian prairies (Chapter 6), Northern Bobwhite in Georgia and Florida (Chapter 7), and shorebirds nesting in the Arctic (Chapter 8). We end with a look at nocturnal activity in shrub and grassland birds, where we see patterns in the role of sleep and activity through the night (Chapter 9). Our understanding of many of the details of these aspects of nesting behavior are sketchy at best, and these chapters are valuable in showing us how much more we can learn using camera technology. The last major section focuses on the use of cameras to measure predation rates and identify predators. We begin with a focus on more classical predation studies, starting with a look at daily

survival rates of grassland nests in Wisconsin (Chapter 10), a study of predation rates and predator identification from Texas (Chapter 11), and then identification of Sprague’s Pipit nest predators from Canada (Chapter 14). Cameras have shown how important snakes are as nest predators in many habitats, so Chapter 12 is very interesting as it shows how the parents attempt to defend nests from snake predation. This section also includes a chapter on partial predation of Northern Bobwhite nests and how losses result in nest abandonment (Chapter 13). All of these chapters provide data that would be difficult if not impossible to gather in any other way. It seems that anyone doing field work would profit by using video cameras, and the last chapter (Chapter 15) shows you how to do this, with instructions on how to make cameras that are relatively inexpensive and very high quality. This volume does an excellent job of showing us the potential for expanded use of video cameras in ornithological studies; I expect that studies such as these will be both common and invaluable in the future.

FOREWORD

JOHN FAABORG

University of Missouri Columbia, Missouri 9 May 2011

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PART ONE

Synthesis/Overview

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CHAPTER ONE

Knowledge Gained from Video-Monitoring Grassland Passerine Nests Pamela J. Pietz, Diane A. Granfors, and Christine A. Ribic

Abstract. In the mid-1990s, researchers began to adapt miniature cameras to video-record activities at cryptic passerine nests in grasslands. In the subsequent decade, use of these video surveillance systems spread dramatically, leading to major strides in our knowledge of nest predation and nesting ecology of many species. Studies using video nest surveillance have helped overturn or substantiate many long-standing assumptions and provided insights on a wide range of topics. For example, researchers using video data have (1) identified an extensive and highly dynamic predator community in grasslands that varies both temporally (e.g., by time of day, nest age, season, year) and spatially (e.g., by habitat, edge, latitude); (2) shown that sign at nests is unreliable for assigning predator types and sometimes nest fates; (3) contributed to the

understanding of the risks and rewards of nest defense; and (4) provided information on basic breeding biology (e.g., fledging ages, patterns of incubation and brooding, and male/female roles in parental care). Using examples from grasslands, we highlight accumulated knowledge about activities at the nest documented with video surveillance; we also discuss the implications of this knowledge for our understanding of avian ecology. Like all tools, video nest surveillance has potential limitations, and users must take precautions to minimize possible sources of bias in data collection and interpretation.

n the 1990s, the plight of grassland birds received increased attention (Johnson and Schwartz 1993, Knopf 1994, Johnson and Igl 1995), as researchers began to recognize that grassland species were showing “steeper, more consistent, and more geographically wide-spread declines than any other behavioral or ecological guild” of North American birds (Knopf 1994:251). Many grassland passerine populations had been declining for decades

(Peterjohn and Sauer 1993, Herkert 1995, Igl and Johnson 1997), and it was thought that high rates of nest predation could be contributing to these declines (Basore et al. 1986, Martin 1993). At that time, there were few data on the identity of nest predators of grassland passerines. Predator sign at grassland duck nests had been studied intensively (Sargeant et al. 1993, 1998); however, at passerine nests, assignment of nest fates and identity

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Key Words: avian behavior, breeding ecology, camera, grassland, nest monitor, nest predators, passerine, video surveillance.

Pietz, P. J., D. A. Granfors, and C. A. Ribic. 2012. Knowledge gained from video-monitoring grassland passerine nests. Pp. 3–22 in C. A. Ribic, F. R. Thompson III, and P. J. Pietz (editors). Video surveillance of nesting birds. Studies in Avian Biology (no. 43), University of California Press, Berkeley, CA.

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A

B

C

E

D

Figure 1.1. Components of video surveillance system used during 1996–2001 to monitor grassland passerine nests in North Dakota and western Minnesota: (a) camera with LEDs around lens; housing and mounting bracket painted to blend with vegetation; (b) camera mounted on wooden dowel above a nest; (c) after placing a camera, R. J. Fletcher, Jr., checks the camera view with a handheld monitor at the nest site; (d) E. M. Madden remotely checks a nest with handheld monitor attached to VCR; VCR is inside weatherproof case with external connectors for battery and monitor; (e) weatherproof case open and VCR tilted up to change videotape.

of predators were usually based on assumptions (Best 1978, Wray et al. 1982, Vickery et al. 1992). Often, when a passerine nest was revisited, only an empty bowl remained, with few or no clues as to what had happened (Hussell 1974, Major and Gowing 1994). Determining fates of grassland bird nests by direct observation generally is not feasible. Nests of many species of grassland birds are well hidden in vegetation, making it difficult or impossible to view nest contents from a distance, and are in open terrain, making unobtrusive observation a challenge. Predator communities often include both nocturnal and diurnal nest predators, which would require 24-hr surveillance. Identifying fates and predators of active grassland passerine nests could not be adequately addressed using artificial nests, still cameras, or conspicuous equipment (Pietz and Granfors 2000a). The need for a new tool was evident. In 1996, Pietz and Granfors (2000a) began testing a video surveillance system (hereafter camera system) specifically designed to monitor grassland

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passerine nests. This first system used a blackand-white camera, about 4 ⫻ 4 cm on each side, with infrared (940–950 nm) light-emitting diodes (LEDs) to cryptically illuminate the nest area at night (Fig. 1.1a). Cameras had to be close to the nests (typically ⬍30 cm) to record activity at the nests and the fate of nest contents without vegetation obstructing the view (Fig. 1.1b). Cameras, in waterproof housings, were made as small as possible to minimize disturbance to the nesting birds and to avoid attracting other animals. The camera angle and placement were adjusted at the nest with the aid of a handheld video monitor (Fig. 1.1c). The camera was connected by cable to a time-lapse videocassette recorder (VCR) and battery (Fig. 1.1d) about 40–50 m away. VCRs were set to record continuously and capture about 4 images/sec because early trials showed that some predation events took only a fraction of a second. At this recording speed, videotapes had to be changed (Fig. 1.1e) daily. The person changing the tape connected a handheld video monitor to the VCR (Fig. 1.1d) to determine (with reasonable certainty) if the nest was NO. 43

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still active, thus eliminating the need to physically revisit the nest. The camera was left in place until the nest failed or succeeded (i.e., fledged young). Camera systems were deployed as far apart as possible within and among study sites to reduce the chance that individual predators with large home ranges [e.g., fox (Vulpes spp.), coyote (Canis latrans)] would encounter more than one nest with a camera. From the mid-1990s through the early 2000s, these or similar camera systems were used in a variety of grassland bird studies (Winter et al. 2000, Renfrew and Ribic 2003, Klug 2005, Grant et al. 2006). The purpose of this paper is to use this body of work and the papers in this volume to provide an overview of the contributions these camera systems have made to the understanding of grassland bird ecology. We include updated test results for some of the questions explored with smaller data sets by Pietz and Granfors (2000a). With these sources of information, we address the following topics: fates of nests, eggs, and nestlings; predator identification and predator ecology; standard methods of data collection and analyses; predator behavior and predator–prey interactions; and parental and nestling behaviors. We close with caveats related to the use of cameras at nests and the interpretation of data collected with camera systems.

FATES OF NESTS AND NEST CONTENTS Studies using video nest surveillance (hereafter camera studies) confirmed that predation was the leading cause of nest failure for grassland passerines (Pietz and Granfors 2000a, Klug 2005, Renfrew et al. 2005, Ribic et al., chapter 10, this volume). In addition, video data revealed that some successful nests (i.e., at least one young fledged) lost part of their contents to predators (i.e., partial predation) (Pietz and Granfors 2005). Results from studies in North Dakota and Minnesota showed that predation not only accounted for most nest losses (Table 1.1) but also was the leading cause of mortality among nestlings (Table 1.2). Camera studies revealed that partial predation sometimes led to nest abandonment by the parents [e.g., in Northern Bobwhite (Colinus virginianus); Ellis-Felege et al., chapter 13, this volume]. Abandonment also occurred at some passerine nests subjected to cowbird parasitism and removal

of host eggs (Hill and Sealy 1994, Romig and Crawford 1995). Video data allow researchers to link proximate events (e.g., egg removal) with nest fates; however, classifying such nests may then become ambiguous using current terminology. For instance, in the examples above, should the cause of nest failure be considered predation or parental abandonment? Parental abandonment also may be caused by deployment of cameras near nests, particularly during the egg stage (Pietz and Granfors 2000a). Nest abandonment that occurred ⬍1 day after camera deployment was assumed to be induced by the nesting birds’ intolerance for the presence of the camera, the disturbance caused while setting up the camera system, or both. In a sample of passerine nests monitored during 1996–2001, 31 of 37 abandonments occurred within 1 day of camera deployment and, thus, were considered to be camera induced (Table 1.1). In the 1996–2001 sample, nearly 22% of 137 nests were abandoned within 1 day when the camera system was deployed during egg laying or incubation; only one such abandonment occurred (⬍2%) among 51 nests when the camera system was deployed during or after hatch. Nest failures attributed to cameras are discussed in the “Caveats” section. In addition to predation, video surveillance revealed factors leading to nest failure or loss of eggs or nestlings that may have been misclassified as predation in the absence of video data (Pietz and Granfors 2000a). For example, two Clay-colored Sparrow (Spizella pallida) nests in small shrubs gradually tipped over as the nestlings grew, and the nestlings suddenly fell out. Unless the nestlings were still present (e.g., on the ground) when the observer returned to check the nest, the observer would have found only an empty, disheveled nest that appeared to have been torn from the shrub by a predator. Video data also showed that some nestlings left the nest prematurely, seemingly on their own accord (here we define “prematurely” as earlier than expected based on fledging ages from undisturbed nests). For example, at a cameramonitored Savannah Sparrow (Passerculus sandwichensis) nest in Minnesota, a small plains gartersnake (Thamnophis radix) attempted to remove 7-d-old nestlings but failed. One nestling left the nest during the snake’s visit and the remaining four nestlings departed within the next 1.5 hr. Video data from undisturbed nests showed that

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TABLE 1.1

Fates of 188 grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001.

Destroyed Common name

Scientific name

Common Yellowthroat

Geothlypis trichas

Clay-colored Sparrow

Spizella pallida

Vesper’s Sparrow

Pooecetes gramineus

Savannah Sparrow

Passerculus sandwichensis

Total nests

Abandoned

1 75

Depredated

Other loss

Censored

Fledged

2

1

6

34

1 15

6

17 4

59

9 1 1

15

Grasshopper Sparrow

Ammodramus savannarum

4

Baird’s Sparrow

Ammodramus bairdii

3

Le Conte’s Sparrow

Ammodramus leconteii

2

Song Sparrow

Melospiza melodia

2

Chestnut-collared Longspur

Calcarius ornatus

9

Bobolink

Dolichonyx oryzivorus

23

Red-winged Blackbird

Agelaius phoeniceus

1

Western Meadowlark

Sturnella neglecta

3

2

1

188

37

49

Total nests

Other

2 1

8

26 3

1

1 1

1

1

1

2

4

3

7

4

12

1 3

2

14

83

NOTES: Nest abandonment ⬍1 d after camera deployment was assumed to be induced by the nesting birds’ intolerance for the camera’s presence and/or disturbance during camera-system setup. Thirty-one nest abandonments were classified as camera induced. In four abandonments that occurred later, nestlings may have been orphaned (two Clay-colored Sparrow nests, one Savannah Sparrow nest, one Bobolink nest). Two nest abandonments (one Clay-colored Sparrow, one Savannah Sparrow) occurred after Brown-headed Cowbirds punctured or removed host eggs and (in the latter case) laid a cowbird egg. Destroyed nests that were not depredated included one Clay-colored Sparrow nest from which a Brown-headed Cowbird tossed out the nestlings (see Notes to Table 1.2), one Clay-colored Sparrow nest from which the young fell out as the nest tipped over, and one Savannah Sparrow nest from which an adult Savannah Sparrow (presumed parent) tossed out the young. Other nest losses included nestling starvation (one Clay-colored Sparrow nest) and all eggs addled (one Le Conte’s Sparrow nest). Censored indicates that the nest fate was not captured on video, either because equipment failed (six nests) or because the camera was removed before the nest fate was determined (eight nests). Nests were classified as fledged if at least one nestling left the nest.

TABLE 1.2 Fates of eggs and nestlings at grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001.

Eggs Fate

Cause

Destroyed

Predator

Host

Cowbird

72

140

11

Cowbird

6

10

Parent

1

2

Unhatched

21

Tipped out

5

Weather

2

Camera

1 117

Predator

2

Cowbird

3

Unknown

1

Addled

43

1

1 3

3

2 16 4 1

Laid too late Hatch/fledge

Cowbird

Starvation

Unknown Abandoned

Host

Nestlings

216

2

Forced by predator

22

1

Forced by observer

7

Normal

353

13

1

Tipped out

NOTES: Although Brown-headed Cowbird is listed as a “predator” in Tables 1.3 and 1.4, it is listed separately from predators as a cause of loss both here and in Table 1.1 for the benefit of those interested specifically in cowbird effects. Cowbird = Brown-headed Cowbird throughout this table. Destroyed tipped-out nestlings include four 2-d-old Clay-colored Sparrow nestlings which died after falling out of their nest (47 cm above ground level) as it tipped completely over, and one 5-d-old Clay-colored Sparrow nestling which fell out as the nest (44 cm high) tipped over on its side. Abandonments ⬍1 d after camera deployment were classified as caused by cameras. Hatch/fledge tipped-out nestling was from a Clay-colored Sparrow nest (44 cm high) that had been gradually tipping sideways; an 8-d-old host young left on its own but, a few hours later, the nest bowl tipped over and an 8-d-old cowbird fell out.

Savannah Sparrow nestlings usually do not fledge until they are 9–10 days old (Pietz et al., chapter 4, this volume). Many cases of “forced fledging” (sensu Pietz and Granfors 2000a) took place while a predator was still at the nest. In such cases, the young were clearly motivated to leave the nest by the presence of the predator, but classifications of nest and nestling fates remain ambiguous. At one Savannah Sparrow nest in North Dakota, a 7-d-old nestling fled the nest while a white-tailed deer (Odocoileus virginianus) was eating its nest mates (Pietz and Granfors 2000b). Technically, the young bird that

left the nest would have been considered a fledgling. In this case, however, the fate of the “fledgling” was known because the deer caught it while it was still in camera view; it survived ⬍10 sec outside the nest (Pietz and Granfors 2000b). Forced fledging occurred at nearly 20% of our nests that were visited by predators and accounted for about 10% of young that were classified as fledged (Table 1.2; Pietz et al., chapter 4, this volume). People checking nests also can cause premature or forced fledging. In one case, three Claycolored Sparrow nestlings stayed still while an observer was at the nest, but they all left the nest

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less than a minute after the person departed (table 3 in Pietz and Granfors 2000a). How forced fledging affects survival of those individuals is seldom known. Certainly, if nestlings are sufficiently ambulatory, forced fledging may be advantageous for nestling survival (Lima 2009). Camera studies have revealed that the determination of nest fates is not always as clear-cut as depicted in the literature. As more studies collect nest data using video, researchers may need to set new standards for terminology and for classifying nest and nestling fates.

PREDATOR IDENTIFICATION AND ECOLOGY Researchers have investigated many factors that potentially affect nest predation. In this extensive literature, there are studies that draw opposite conclusions regarding the effects of just about every factor tested—including nest concealment, nest stage, habitat edge, and landscape characteristics (e.g., references in Pietz and Granfors 2000a, Jones and Dieni 2007). One likely explanation for these conflicting results is that the predator communities differed among studies. Before we can understand the ecological factors and underlying mechanisms that govern nest predation, we must first know who the predators are (Lahti 2009; Weidinger 2009, 2010; Benson et al. 2010; Thompson and Ribic, chapter 2, this volume). Video surveillance at nests has helped researchers to do this. Camera studies have revealed a surprising diversity of predators at grassland passerine nests. For example, in the North Dakota and Minnesota studies (1996–2001), there were 16 different predators identified to the level of genus or species, including 11 mammals, four birds, and one snake (Table 1.3). Similar levels of diversity were found in other grassland studies (Table 1.4; Davis et al., chapter 14, this volume). In addition to confirming culpability by species assumed to be nest predators, camera studies have documented unsuspected nest predators, such as jumping mice (Zapus spp.) and white-tailed deer (Pietz and Granfors 2000a, 2000b), as well as cattle (Bos taurus) (Nack and Ribic 2005). Video data have allowed researchers to start exploring how nest predator communities vary at multiple spatial scales. Grassland camera studies across several states, from Wisconsin to Montana 8

STUDIES IN AVIAN BIOLOGY

and south to Nebraska, have illuminated some regional similarities and differences in predator communities (Table 1.4). Unsurprisingly, raccoons (Procyon lotor) were documented more often at eastern study sites (e.g., Renfrew and Ribic 2003), where the mix of row-crop agriculture [particularly corn (Zea mays)] and woodlands provides quality habitat for raccoons (Dijak and Thompson 2000). Some differences in predator communities reflect latitudinal ranges of taxa. For example, in the more northerly grasslands (Montana, North Dakota, and Minnesota), snakes accounted for less than 5% of nest predation events in which predators were identified, and these all were by gartersnakes (Thamnophis spp.) (Table 1.4). Farther south, however, the number of snake species and the proportion of snake predations increased markedly. For instance, in Nebraska and Iowa, snake species accounted for more than one-third of nest predations (Table 1.4). The disparity in prevalence of snake predation between cool and warm climates has been documented beyond grasslands (King and DeGraaf 2006). At smaller spatial scales, researchers are just beginning to investigate how predator communities differ among different grassland habitats (Ribic et al., chapter 10, this volume). Understanding how predator communities vary spatially can be used to help guide grassland bird conservation efforts (Thompson and Ribic, chapter 2, this volume). Predator communities also can vary temporally, such as across seasons and years. On an extremely long temporal scale, distributions of some snake species and other nest predators that are currently limited by temperature (e.g., fire ants) may change as a result of warming associated with climate change. At the opposite extreme, video surveillance has allowed researchers to examine predation at much finer temporal scales by pinpointing the exact time that predation events occur. This information has prompted new ways of looking at predation ecology. Knowing the time of predation allows researchers to explore differences between nocturnal and diurnal nest predators. For example, predators hunting during the day have more visual cues available to them, whereas nocturnal predators probably rely more on scent. This led us (the authors) to expect that diurnal predators would find nests with open bowls more easily than nests with covered bowls, but that nest type would be less likely to matter to nocturnal predators. NO. 43

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TABLE 1.3 Predators documented at grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001.

1996

Predator

1998

8

Thirteen-lined ground squirrel

3

8

2001

Total

1

6

1

20 2

1

1

2 2

Unidentified mouse/vole

2

1

1 1

Red fox Long-tailed weasel

2000

2

Deer mouse Coyote or red fox

1999

5

Franklin’s ground squirrel Jumping mouse

1997

1

1

1

Ermine

1

1

Least weasel or ermine

1

1

2

American badger

1

2

Striped skunk 1

1

Northern Harrier

1

Buteo hawk

1

1

2

1

Plains gartersnake

2

1

4

1

1

3

Unidentified

Total nests with cameras

6 4

1 1

1 1

9 2

Gartersnake

Total predation events

2 1

1 1

3 1

1

American Kestrel Brown-headed Cowbird

6 2

1

Raccoon White-tailed deer

1 1

1

1

2

1

1

7

6

23

9

21

11

9

79

17

52

29

35

27

28

188

NOTES: In 1996 and 1997, data were collected in Stutsman and Barnes counties, southeastern North Dakota (Pietz and Granfors 2000a). In 1998 and 1999, data were collected at J. Clark Salyer National Wildlife Refuge, Bottineau and McHenry counties, northcentral North Dakota, in collaboration with U.S. Fish and Wildlife biologists (Grant et al. 2006). In 2000 and 2001, data were collected at several sites in Polk County, northwestern Minnesota, in collaboration with Maiken Winter and Douglas H. Johnson’s evaluation of Bird Conservation Areas (Winter et al. 2000, 2001, 2006). See Figure 2.1 of Thompson and Ribic (chapter 2, this volume) for a map of the counties in which data were collected. Scientific names of predators are given in Table 1.4. We defined a predation event as any nest visit resulting in removal or destruction of ⱖ1 egg or nestling by a single individual (or species, if individuals could not be distinguished). In 2001, a Northern Harrier removed a nestling but did not eat it; the nestling later died outside the nest bowl, so we considered this a predation event. Scavenging events (1997 jumping mouse and 1996 red fox) and forced-fledging events (1999 unidentified mouse/vole and 2000 plains gartersnake) are not included in the table. Some nests were visited by multiple predators: one nest was depredated by both a thirteen-lined ground squirrel and an unidentified mouse or vole; one was depredated by both a Northern Harrier and a striped skunk; and two nests were visited by other predators/scavengers after visits by cowbirds.

To test this idea, we determined the time when a predator first removed (or destroyed) an egg or nestling from a nest. We called this the “initial predation” (sensu Pietz and Granfors 2000a) and, because it likely reflected conditions under which the predator found the nest, we used it as a

measure of predation risk. We calculated separate rates of initial predation for day and night, using nest data from our North Dakota and Minnesota studies (1996–2001). As predicted, open nests tended to be more vulnerable than covered nests during the day, whereas at night predation risks

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TABLE 1.4 Predators documented at grassland passerine nests monitored with video surveillance systems during several studies in the northern prairies and the Midwest.

Common name

Scientific name

Mammals Virginia opossum

Didelphis virginiana

Montana

North Dakota

Minnesota

Nebraska/Iowa

Wisconsin 3

Franklin’s ground squirrel

Poliocitellus franklinii

5

1

1

Thirteen-lined ground squirrel

Ictidomys tridecemlineatus

19

1

3

Jumping mouse

Zapus spp.

2

Vole

Microtus spp.

Deer or white-footed mouse

Peromyscus spp.

4 1

2

2 1

2

Mouse or vole

22

Domestic cat

Felis catus

2

Coyote

Canis latrans

3

Domestic dog

Canis lupus familiaris

1

Red fox

Vulpes vulpes

1

1

Fox or coyote Ermine

1

Long-tailed weasel

Mustela frenata

Least weasel

Mustela nivalis

Weasel

Mustela spp.

American mink

Neovison vison

American badger

Taxidea taxus

2 1

Mustela erminea 1

1

1 2 1

5

1

3

3

Striped skunk

Mephitis mephitis

Raccoon

Procyon lotor

1

White-tailed deer

Odocoileus virginianus

4

Domestic cattle

Bos taurus

16 6

2

19 4 4

Birds Northern Harrier

Circus cyaneus

Red-tailed Hawk

Buteo jamaicensis

Buteo hawk

Buteo spp.

American Kestrel

Falco sparverius

Western Meadowlark

Sturnella neglecta

Eastern Meadowlark

Sturnella magna

Brown-headed Cowbird

Molothrus ater

3

1

3 3

2

2 1

2 1 7

2

2

3

Reptiles North American racer

Coluber constrictor

Milksnake

Lampropeltis triangulum

Western foxsnake

Mintonius vulpinus

Bullsnake

Pituophis catenifer sayi

Gartersnake

Thamnophis spp.

1 5 5

9

1 1

2

1

2

4

NOTES: Numbers in the columns represent predation events: nest visits resulting in removal or destruction of ⱖ1 egg or nestling by a single individual (or species, if individuals could not be distinguished). Scavenging and forced-fledging events are not included. Sources for predator data are as follows: in Montana, Davis et al. (chapter 14, this volume); in North Dakota, Pietz and Granfors (2000a, 2000b, and unpubl. data) and Grant et al. (2006); in Minnesota, Winter et al. (2000, 2001); in Nebraska/Iowa, Klug et al. (2010); in Wisconsin, Renfrew and Ribic (2003), Nack and Ribic (2005), Ribic et al. (chapter 10, this volume), and C. A. Ribic, U.S. Geological Survey, and K. Ellison, Wildlife Conservation Society (unpubl. data). Scientific names and taxonomic order follow Wilson and Reeder (2005) for mammalian species and Crother (2008) for reptiles. Gartersnake includes plains (Thamnophis radix), common (T. sirtalis), and unidentified species of gartersnakes. In Wisconsin, the predator listed as a domestic dog might have been a coyote.

Figure 1.2. Initial-predation rates during day and night for nests that were and were not covered by vegetation (open vs. covered), from a sample of grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001. Mean difference in initialpredation rates between open and covered nests during the day was 0.022 ⫾ 0.010 SE (␹21 ⫽ 5.26, P ⫽ 0.02) and during the night was 0.003 ⫾ 0.006 (␹21 ⫽ 0.15, P ⫽ 0.69). Sample sizes for open and covered nests were 718 and 625 camera nest-days (i.e., number of days active nests were monitored with cameras), respectively.

(i.e., initial-predation rates) for the two nest types were similar (Fig. 1.2). The same result was found in an earlier analysis using just 1996–1997 data (Pietz and Granfors 2000a). In that paper, daily predation rates also were reported for nearly 300 nests that were monitored without video surveillance (i.e., non-camera nests); no difference was detected between open and covered non-camera nests (␹21 ⫽ 0.00, P ⫽ 0.98), suggesting that predation risk associated with nest cover may only be detectable if diurnal and nocturnal predation can be separated. The ability to separate diurnal and nocturnal predation events may contribute to deciphering ecological phenomena in unexpected ways. For example, when Roper and Goldstein (1997) tested the Skutch hypothesis that activity at nests increases nest predation risk (Skutch 1949, 1985), they expected to find greater nest predation rates during the nestling stage than during incubation. They found higher frequencies of nest visits by adult birds during the nestling stage than during incubation, but daily survival rates did not differ between the two nest stages. They surmised that this lack of support for the link between nest activity and predation could be explained by the

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STUDIES IN AVIAN BIOLOGY

previously unrecognized importance of predation by a nocturnal mammal, which they assumed did not use bird activity to locate nests. Now video data can be used to help assess the relative importance of nocturnal versus diurnal predation and to test hypotheses related to activity at nests (e.g., Muchai and du Plessis 2005). Knowing the time of predation also allows researchers to explore whether brood age affects predation risk. We tested some of these ideas with nest data from our North Dakota and Minnesota studies (1996–2001). We used initial-predation rates as a measure of predation risk and used brood age as a surrogate for daytime activity at the nest. We expected daytime initial-predation rates to increase with brood age, because some studies have shown that daytime activity of parents and nestlings tends to increase as nestlings grow (e.g., provisioning rates increase with brood age; Goodbred and Holmes 1996, Dohms 2009). We did not expect nocturnal initial-predation rates to increase with brood age, however, because activity at the nest, at all brood ages, typically ceases at night (Roper and Goldstein 1997; authors, unpubl. data). In our sample, nestlings were more likely to be depredated during the day than at night, but we did not find an increase in initial-predation rate with brood age for either day or night (Fig. 1.3; day: rs ⫽ ⫺0.07, P ⫽ 0.85; night: rs ⫽ 0.20, P ⫽ 0.57). Our sample for some brood ages may have been too small to test for this pattern, or the assumption that activity at the nest increases all the way through fledging age may not be true (e.g., see Adler 2010). Video data can be used to examine this assumption, for example, by quantifying adult visits to nests as the nestlings age. Note that we lumped several species in our analysis because of small sample sizes, but we recognize that activity (e.g., provisioning rates) may not relate to nestling age in the same way for all species. In any case, the hypothesis that brood age affects vulnerability to predation needs further testing.

EVALUATING STANDARD METHODS Video surveillance has helped researchers evaluate several standard methods used to study nesting biology, including those used to assign nest fates, causes of nest failure, and (for depredated nests) types of predators. The standard way of determining nest fate is to visit the nest every few days, using nest contents, sign at the nest (including NO. 43

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Figure 1.3. Diurnal and nocturnal initial-predation rates (n ⫽ 130 nests, 876 camera nest-days) for broods aged 0–9 days, from a sample of grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001. Vertical lines represent ⫾1 SE. Brood age was calculated using the hatch day of the first egg as day 0.

Figure 1.4. Parental nest attendance (i.e., visits) after final predation (i.e., when no viable contents remained in nest), from a sample of grassland passerine nests (n ⫽ 20) monitored with video surveillance systems in North Dakota, 1996–1997. Larger circles represent more nests. Hours on the x-axis represent hourly time intervals (e.g., 0 ⫽ within the first hour; 1 ⫽ within second hour). Nests with zero parental visits after the final predation event were not included.

condition of the nest and nest vicinity), and behavior of parent birds to decide if the nest was successful. Earlier video data showed that initial-predation rate tended to increase with nestling age (Pietz and Granfors 2000a), and many nests were depredated when nestlings were close to fledging age (Pietz and Granfors, unpubl. data). At this stage, depredated and fledged nests may be impossible to tell

apart. Even the behavior of parent birds can be misleading. Pietz and Granfors (2000a, unpubl. data) found that parents continued to visit their nests, often carrying food, for several hours after all nest contents had been removed by predators (Fig. 1.4). Visitation rate dropped off quickly, but some parents were still attending nests nearly a day later. Pietz and Granfors (2000a) therefore

VIDEO-MONITORING GRASSLAND BIRD NESTS

13

suggested that researchers check adult behavior on more than 1 day if it is used as the basis for classifying nest fate. Video evidence indicated that some nests failed for reasons other than predation, but the cause of failure might be misconstrued as predation to an observer doing periodic nest checks. For example, when nestlings died at a young age, video showed that the parents sometimes removed the carcasses from the nest (Pietz and Granfors 2000a, Kirkpatrick et al. 2009), resulting in the appearance of predation or partial predation. Another example (Pietz and Granfors 2000a, unpubl. data), involving a Western Meadowlark (Sturnella neglecta) nest in North Dakota, illustrates how difficult it can be to correctly assess cause of failure from nest checks. The meadowlark adults left their five-egg clutch unattended for several hours following human disturbance near the nest site. Then a Brown-headed Cowbird (Molothrus ater) entered the nest bowl, tossed three eggs out of the nest, and punctured holes in the other two eggs. That night, insects scavenged contents from those two eggs, and the following night a red fox (Vulpes vulpes) scavenged the remaining egg contents (and likely removed the three eggs that the cowbird had tossed outside of camera view). When Pietz revisited the site, the only remains were two eggs’ shells that looked similar to those known to have been depredated by small mammals (Pietz, pers. obs.). Prior to camera studies, numerous authors claimed to be able to identify types of nest predators based on the condition of the nest after predation (e.g., Best 1978, Best and Stauffer 1980, Wray et al. 1982, Hoover et al. 1995, Patterson and Best 1996, Christman and Dhondt 1997). Pietz and Granfors (2000a) found that none of their generalizations were valid in North Dakota grasslands. No sign was left at most nests, including those depredated by large mammals. Furthermore, Pietz and Granfors (2000a) found considerable variability within species and overlap among species when they did leave sign (see also Sargeant et al. 1998). Sign can be misleading as well as ambiguous. In Minnesota, for example, a Savannah Sparrow nest from which a four-egg clutch disappeared was found to be surrounded by deer tracks when the nest was checked, but the videotape showed that the eggs had been removed by a male Northern Harrier (Circus cyaneus) (Pietz, unpubl. data). Thus, even when

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STUDIES IN AVIAN BIOLOGY

sign appears obvious, it may lead to the wrong conclusion. Many other camera studies, in several habitats and ecosystems, have shown that sign is unreliable for assigning predator types at passerine nests (e.g., Thompson et al. 1999, McCallum and Hannon 2001, Williams and Bohall Wood 2002, Liebezeit and George 2003, Thompson and Burhans 2003) and non-passerine nests (Ratz et al. 1999, MacDonald and Bolton 2005, Coates et al. 2008, White et al. 2010). Some variation in nest damage by predators might be related to nest height. In North Dakota, for example, a Buteo hawk ripped a Clay-colored Sparrow nest out of a small shrub, completely destroying the nest (Pietz and Granfors 2000a, unpubl. data). Hawks did not appear to damage any of the six ground nests from which they removed eggs or young (Pietz, unpubl. data). Nest predators, in general, were less likely to damage nests that were on the ground than nests that were above the ground (Pietz and Granfors 2000a). This makes sense, given that nests on the ground are easier to reach for most predators and have more structural support than nests that are off the ground and attached to vegetation. As suggested in an earlier section, video nest surveillance has allowed a new approach to the study of predation risk. The use of initial-predation rate provides a better measure of predation risk (e.g., relative to nest stage, nestling age) than does daily survival rate or daily predation rate (Pietz and Granfors 2000a). Daily survival rate is affected by sources of nest loss other than predation and can be affected by misclassified nest fates. The standard daily predation rate (which we refer to as final-predation rate) only includes nests that have lost all their contents and is associated with the time and conditions when loss of the last viable nest contents was detected. Initial predation, on the other hand, more likely coincides with the time and conditions under which a predator first discovered the nest. If partial predation is common, the initial and final daily predation rates could be substantially different. Video nest surveillance also has provided a means to verify natural fledging ages (Pietz et al., chapter 4, this volume). For most species, fledging ages published in the literature (e.g., Ehrlich et al. 1988, Baicich and Harrison 1997) are based on data from researchers visiting nests. However, as mentioned earlier, video data have shown that fledging can be precipitated by a nest visit (e.g., table 3 in Pietz and Granfors 2000a). If NO. 43

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researchers underestimate average fledging ages, it could cause them to conclude that failed nests had fledged and, thus, overestimate nest survival. Video surveillance also offers a means to evaluate impacts of researcher activities at nests. For example, video could allow researchers to gauge parental reactions to markers used on nestlings and data-collecting devices placed in nests (e.g., artificial-egg thermistors or camera triggers). Some studies already have used nest video for such purposes. For example, Fisher et al. (2010) documented that adult Sprague’s Pipits (Anthus spragueii) pulled some radio-marked nestlings from their nests while attempting to remove the nestlings’ transmitters. Little et al. (2009) used video data to assess the response of adult Bobolinks (Dolichonyx oryzivorus) to neck ligatures on their nestlings. Ibáñez-Álamo and Soler (2010) identified nest-predator communities at their study sites with nest video, and then used this information to develop an appropriate experimental design to evaluate effects of nest visits by researchers on predation rates. Contrary to traditional ideas, they demonstrated that investigator activities can reduce nest predation.

PREDATOR–PREY BEHAVIOR Video nest surveillance allows observation of predator and prey behavior and predator–prey interactions that are difficult or impossible to document any other way in grasslands. For example, camera studies have documented multiple individuals (of the same or different species) depredating the

A

same nest (e.g., Table 1.3; Davis et al., chapter 14, this volume, Ellison and Ribic, chapter 12, this volume). Camera studies have also revealed multiple factors that can lead to partial predation. Smaller predators sometimes removed eggs or nestlings over multiple days (Pietz and Granfors 2000a, Davis et al., chapter 14, this volume). In the latter case, some nestlings could survive to fledge even though their nest mates were eaten on earlier predator visits. As discussed previously, partial predation also resulted when predators ate some young and induced forced fledging of others (if those nests are classified as successful). As discussed below, other partial predations may have resulted because parents successfully defended their nests. Because cameras in grasslands typically are set close to nests, many instances of adult nest defense may have occurred outside the camera’s field of view. Nevertheless, numerous cases of adult birds attacking predators have been documented on video (e.g., Fig. 1.5a). Camera systems have captured nest defense by ten species of grassland-nesting passerines against 11 species of mammalian, avian, and reptilian predators (Pietz and Granfors 2005, Davis et al., chapter 14, this volume, Ellison and Ribic, chapter 12, this volume). Defense occurred during both day and night, and was directed at mice, ground squirrels, a raccoon, a long-tailed weasel (Mustela frenata), Brown-headed Cowbirds, and snakes. Camera systems have documented both the risks and rewards of nest defense. For example, after unsuccessfully defending four of her five

B

Figure 1.5. Images from videotape of a Chestnut-collared Longspur (Calcarius ornatus) nest monitored in North Dakota during 1997: (a) The female longspur attacked a thirteen-lined ground squirrel (Ictidomys tridecemlineatus) that was removing a nestling from her nest; despite her defense, a ground squirrel removed four of her five nestlings over two days. (b) On the third day, a ground squirrel captured, killed, and dragged the adult longspur from her nest. Arrows point to the ground squirrel in both images.

VIDEO-MONITORING GRASSLAND BIRD NESTS

15

Figure 1.6. Initial-predation rates (n ⫽ 130 nests, 876 camera nest-days) and nest survival rates (n ⫽ 131 nests, 936 camera nest-days) for broods aged 0–9 days, from a sample of grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001. Vertical lines represent ⫾1 SE. Brood age was calculated using the hatch day of the first egg as day 0. No nests in this sample were initially depredated when the brood was 9 days old. Both diurnal and nocturnal initial-predation events were included in calculating initial-predation rates.

nestlings from ground-squirrel attacks, a female Chestnut-collared Longspur (Calcarius ornatus) was caught, killed, and dragged from her nest by a thirteen-lined ground squirrel (Ictidomys tridecemlineatus) (Fig. 1.5b; Pietz and Granfors 2005), a species not generally considered a threat to an adult bird. Equally surprising was the apparently successful nest defense by a Clay-colored Sparrow against a long-tailed weasel (Pietz and Granfors 2005), a species known to kill adult birds (Keith 1961). In another case, Brown-headed Cowbird attacks on nestlings elicited vigorous defense by a female Bobolink. The female cowbird picked up three nestlings and carried them away, even while the Bobolink landed on her back and pecked her (Pietz and Granfors 2005). One nestling survived to fledge, however, so by definition, this was a successful nest. Depending on the cowbird’s motivation for removing nestlings [e.g., reducing competition for her own young in other nests? (Granfors et al. 2001)], this still could be considered successful predation. Depending on the overall reproductive cost to the Bobolink, this also might be considered successful defense. Nest defense by grassland passerines against snake predators is discussed by Ellison and Ribic (chapter 12, this volume). Factors that contribute to partial predation (e.g., parental defense, small predator size, and forced fledging) can lead to increased nest survival later in the nesting cycle. The probability that some

16

STUDIES IN AVIAN BIOLOGY

young will escape from nest predators increases with nestling age (Halupka 1998b, Grant et al. 2005) and may contribute to increased daily nest survival as nestlings get older, a pattern that has been demonstrated for several species (e.g., Grant et al. 2005, Davis et al. 2006). As a result, even studies that showed an increase in predator attacks late in brood rearing (Halupka 1998a, Pietz and Granfors 2000a) did not find a decrease in daily survival rates with nestling age. Here, we examined this phenomenon further, by evaluating initial-predation rates and nest survival rates for broods aged 0–9 days with data from 1996– 2001 (Fig. 1.6). Our results were similar to those found during 1996–1997 for broods aged 0–8 days (Pietz and Granfors 2000a) in that predators initiated more attacks on 7- and 8-d-old broods than on younger broods. However, predators initiated only two attacks on 6-d-old and none on 9-dold broods, demonstrating the variability in our system and the need for larger samples to examine patterns related to brood age. The data set for Figure 1.6 includes only 49 depredated nests spread across ten brood ages. We could have combined some ages (e.g., 0–4 and 5–9 d; for Fig. 1.3 and Fig. 1.6), but this would have obscured the variability that we observed in the raw data. Probably contributing to this variability was the variety of species in our predator community (Table 1.3), with widely varying diets and foraging NO. 43

Ribic, Thompson, and Pietz

behaviors, undoubtedly using different sensory cues to find prey. Patterns between predation and nestling age have been found in at least one camera study that focused on a single predator group. Stake et al. (2005) found that snake predation increased through the nesting cycle, reaching the highest rate during the last few days of the nestling period. They concluded that avian activity contributed to foraging success of snakes at their sites.

PARENTAL AND NESTLING BEHAVIORS Video nest surveillance is helping to fill gaps in basic knowledge of nesting biology, especially for species that are difficult to observe directly. As noted earlier, nests and activity at nests of many species of grassland birds are difficult or impossible to observe directly. Thus, it is not surprising that the Birds of North America accounts (Poole 2005) for many grassland bird species provide little or no information on many aspects of parental behavior. For example, in the account for Baird’s Sparrow (Ammodramus bairdii), Green et al. (2002) state that there is no information about the parents’ time on and off the nest during incubation, and the data provided on parental care during brooding are based on observations at three nests more than 80 years ago (Cartwright et al. 1937). In the account for Claycolored Sparrows, Knapton (1994) provides percentages of male and female incubation time based on 3 hr of observations at one nest nearly 50 years ago (Fox 1961). Several chapters in this volume of Studies in Avian Biology illustrate how video data are filling gaps in our knowledge of parental care and nesting biology (e.g., Burnam et al., chapter 7, this volume, Davis and Holmes, chapter 6, this volume, Powell et al., chapter 5, this volume, Slay et al., chapter 9, this volume, Smith et al., chapter 8, this volume). Video data also have provided unexpected information, such as the documentation of a helper at a nest of a Henslow’s Sparrow (Ammodramus henslowii, Guzy et al. 2002). Recent advances in statistical modeling techniques have allowed nest survival to be examined in unprecedented detail (see papers in Jones and Geupel 2007). Use of the logistic-exposure method (Shaffer 2004) has shown complex and sometimes unexpected relationships between nest survival and nest age (Grant et al. 2005, Davis et al. 2006). For example, some grassland passerines showed a drop in daily nest survival through the incubation period (Grant et al. 2005). Video

data have been used to explore the possibility that changes in parental nest activity through incubation might be linked to this pattern (Grant et al. 2005; T. L. Shaffer, P. J. Pietz, and D. A. Buhl, U.S. Geological Survey, unpubl. data). Among grassland birds, parental provisioning rates to nestlings of different ages have been documented with video for Grasshopper Sparrows (Ammodramus savannarum) (Adler 2010) and Sprague’s Pipits (Dohms 2009). As we have seen, video data can provide a means to explore potential explanations for age- and time-specific variation in passerine nest survival. Data on behavior of grassland nestlings are even more difficult to obtain than data on behavior of adult grassland passerines. Video surveillance already has provided some information on natural fledging ages for grassland passerines, and on the length of hatching and fledging periods in a sample of nests (e.g., Pietz et al., chapter 4, this volume). More data need to be collected under natural and experimental conditions to shed light on factors that could influence these phenomena. Appropriately placed cameras also could allow researchers to evaluate nestling reactions to disturbance and how those reactions change with nestling age. For example, field biologists have observed anecdotally that nestlings of some species respond to humans at the nest by begging when they are young, but remain quiet and still when they are older (T. A. Grant, U.S. Fish and Wildlife Service, pers. comm.; L. D. Igl, U.S. Geological Survey, pers. comm.). Video data could be used to assess if this behavioral change is common and what factors may influence it (e.g., species, habitat, type of disturbance). Interest in how nestling behavior relates to predation risk has prompted numerous experimental studies of begging (e.g., Dickens and Hartley 2007, Dor et al. 2007, Haff and Magrath 2010), but little on nest exodus (Kleindorfer et al. 1996, Lima 2009). Some authors have speculated that well-developed nestlings under attack would not flee the nest (i.e., force fledge) unless their parents directed them to do so (reviewed in Lima 2009). For camera studies of begging behavior or responses to parental calls, researchers would need to incorporate sound recording into their camera systems. Video surveillance also may provide insights on parental and nestling reactions to severe weather events and other unpredictable disturbances, as

VIDEO-MONITORING GRASSLAND BIRD NESTS

17

well as on the impacts of those disturbances. In Montana, for example, when a hailstorm pounded the video-monitored nest of a Baird’s Sparrow, the adult fled and the nestlings died (P. J. Gouse, U.S. Fish and Wildlife Service, pers. comm.). This is another example of how knowledge of circumstances might affect nest-fate classification.

CAVEATS Video nest surveillance has been instrumental in moving the field of avian ecology forward; however, like every tool, it has limitations. As with all studies of active nests, it is important to minimize effects on the nesting birds, for ethical and conservation reasons (e.g., see Fair et al. 2010) and to protect against biasing the data collected. Several researchers (e.g., Pietz and Granfors 2000a, Renfrew and Ribic 2003, Stake and Cimprich 2003) noted that nest abandonment was greater for nests with cameras than for those without cameras, and made adjustments in methods in an effort to reduce these abandonments (Richardson et al. 2009). Because abandonment risk likely varies by species, camera distance, nest age, and other factors, researchers need to evaluate risk within the specific conditions dictated by their study objectives. For predation studies, researchers should be aware that the presence of cameras (and the associated equipment) might affect nest visitation by some types of predators (Richardson et al. 2009), especially when cameras are placed close to nests. Populations (or individuals) of some species may be attracted or repelled by novel items and human scent (see discussion in Pietz and Granfors 2000a), depending on the extent to which they have had negative interactions with humans (Birkhead 1991:221, Götmark 1992:80) or have become habituated to human presence. Reports persist that the presence of cameras may increase nest survival, especially during incubation (Conner et al. 2010). However, Richardson et al. (2009) reviewed some sources for this bias that are unrelated to predator behaviors (e.g., a nest usually must survive longer to receive a camera and thus be included in the treatment group), and acknowledged that these factors complicate efforts to synthesize camera effects. Researchers might bias predation data by how they spatially deploy multiple camera systems (Pietz and Granfors 2000a). If nests with cameras 18

STUDIES IN AVIAN BIOLOGY

are clustered, they will be exposed to fewer individuals (especially of species with large home ranges); the same individual may depredate multiple nests and may learn to associate cameras with nests. Such associative learning has been noted for some predators that ostensibly linked nest locations with markers placed up to 5 m away (e.g., Picozzi 1975, Reynolds 1985). Richardson et al. (2009:292) listed nine recommendations to “minimize or control for potential bias when using surveillance cameras.” Among these was the suggestion to “maintain similar rates of nest visitation for nests with and without cameras.” Controlling for visitation rates would be sensible for researchers interested in measuring the effects of just the camera’s presence on nest survival rates (e.g., McKinnon and Bêty 2009); however, others may argue that this suggestion defeats one of the original purposes of video surveillance, namely to acquire data remotely without the disturbance of repeated nest visits. Some of the nest predator communities documented by video are trophically complex. For example, many of the species identified in grasslands are opportunistic foragers, and some nest predators can be primary or alternative prey for other predators. In addition, nest predator communities and the species in them can be spatially and temporally dynamic for many reasons, including food availability, changes in human land use, and disease. For example, during our studies in North Dakota and Minnesota, skunk and canid populations in some areas were reduced by rabies and mange, respectively (Pietz and Granfors 2000a). Researchers need to keep this dynamic complexity in mind so that their conclusions are drawn at the correct temporal and spatial scales. Temporal and spatial variability in our predator community in northern grasslands is illustrated in Table 1.3; for example, among the six years (areas) of data collection shown, nest predation by ground squirrels ranged from absent to dominant. Another factor to keep in mind is that identification of individuals may not be possible without auxiliary markers. Even with color imagery, it may not be possible to distinguish male from female parents, or the parent from a non-parent conspecific (e.g., a helper; Guzy et al. 2002), especially for monomorphic species without sexually dichromatic plumage. Similarly, multiple appearances NO. 43

Ribic, Thompson, and Pietz

at a nest by the same predator species may involve one or more individuals. Naturally occurring differences sometimes can be used to separate individuals (e.g., a molted feather, a scar, or body size). In general, however, researchers should be careful not to make unsubstantiated assumptions about parent birds or predators. Video data acquired by monitoring nests with miniature cameras have improved our ability to address old questions, allowed us to confirm or refute long-held assumptions, and opened up entirely new areas of investigation. For example, video data are uniquely suited to document some temporal aspects of predation (e.g., time of day, nest age) and have provided new ways of measuring predation risk. The promise of video data from nests, however, depends on researchers making the effort to properly adapt camera systems to their situation. Every tool has potential shortcomings and, to minimize these, investigators must take care to design a system that suits the species, habitats, and environments in which they work. To avoid potential biases and erroneous conclusions, and to improve the quality and value of findings, care also must be taken in analyzing and interpreting video data. We hope this chapter and others in this volume will help those planning to collect and those currently collecting video data at nests.

ACKNOWLEDGMENTS We thank our research collaborators T. J. Anderson, K. S. Ellison, P. J. Gouse, T. A. Grant, M. J. Guzy, D. H. Johnson, S. L. Jones, E. M. Madden, J. L. Nack, R. B. Renfrew, D. W. Sample, J. A. Shaffer, and M. Winter. We also thank all the field technicians who helped collect the data used in this paper. D. A. Buhl and G. A. Sargeant provided help with statistical analyses. Camera systems were built by J. Christensen, J. Dadisman, K. S. Ellison, R. Fuhrman, and D. K. Garcelon. Mention of trade names or commercial products does not constitute endorsement for use by the U.S. government. Financial support was provided by U.S. Geological Survey, Northern Prairie Wildlife Research Center, U.S. Fish and Wildlife Service (Regions 6 and 3 Nongame Bird Conservation Programs, and J. Clark Salyer National Wildlife Refuge), and Wisconsin Department of Natural Resources. L. D. Igl, S. L. Jones, and F. R. Thompson III provided thoughtful reviews of earlier versions of this paper. Special thanks to L. D. Igl, who provided references and advice throughout the development of this chapter.

LITERATURE CITED Adler, J. 2010. Provisioning behavior of male and female Grasshopper Sparrows. M.S. thesis, Eastern Kentucky University, Richmond, KY. Baicich, P. J., and C. J. O. Harrison. 1997. A guide to the nests, eggs, and nestlings of North American birds. Academic Press, San Diego, CA. Basore, N. S., L. B. Best, and J. B. Wooley, Jr. 1986. Bird nesting in Iowa no-tillage and tilled cropland. Journal of Wildlife Management 50:19–28. Benson, T. J., J. D. Brown, and J. C. Bednarz. 2010. Identifying predators clarifies predictors of nest success in a temperate passerine. Journal of Animal Ecology 79:225–234. Best, L. B. 1978. Field Sparrow reproductive success and nesting ecology. Auk 95:9–22. Best, L. B., and D. F. Stauffer. 1980. Factors affecting nesting success in riparian bird communities. Condor 82:149–158. Birkhead, T. 1991. The magpies. T. & A. D. Poyser, London, UK. Cartwright, B. W., T. M. Shortt, and R. D. Harris. 1937. Baird’s Sparrow. Transactions of the Royal Canadian Institute 21:153–197. Christman, B. J., and A. A. Dhondt. 1997. Nest predation in Black-capped Chickadees: how safe are cavity nests? Auk 114:769–773. Coates, P. S., J. W. Connelly, and D. J. Delehanty. 2008. Predators of Greater Sage-Grouse nests identified by video monitoring. Journal of Field Ornithology 79:421–428. Conner, L. M., J. C. Rutledge, and L. L. Smith. 2010. Effects of mesopredators on nest survival of shrub-nesting songbirds. Journal of Wildlife Management 74:73–80. Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico. Herpetological Circular No. 37. Society for the Study of Amphibians and Reptiles, Salt Lake City, UT. Davis, S. K., R. M. Brigham, T. L. Shaffer, and P. C. James. 2006. Mixed-grass prairie passerines exhibit weak and variable responses to patch size. Auk 123:807–821. Dickens, M., and I. R. Hartley. 2007. Stimuli for nestling begging in Blue Tits Cyanistes caeruleus: hungry nestlings are less discriminating. Journal of Avian Biology 38:421–426. Dijak, W. D., and F. R. Thompson III. 2000. Landscape and edge effects on the distribution of mammalian predators in Missouri. Journal of Wildlife Management 64:209–216. Dohms, K. M. 2009. Sprague’s Pipit (Anthus spragueii) nestling provisioning and growth rates in native and planted grasslands. M.S. thesis, University of Regina, Regina, Saskatchewan, Canada.

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Dor, R., H. Kedar, D. W. Winkler, and A. Lotem. 2007. Begging in the absence of parents: a “quick on the trigger” strategy to minimize costly misses. Behavioral Ecology 18:97–102. Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder’s handbook. Simon and Schuster, New York, NY. Fair, J. M., E. Paul, and J. Jones (editors). 2010. Guidelines to the use of wild birds in research. Third edition. The Ornithological Council, Washington, DC. 60

Figure 13.1. Frequency of nest abandonment (± 95% confidence intervals) by attending Northern Bobwhites (Colinus virginianus) following partial depredation events by percentage of eggs remaining after event. Scalar unit of analysis was 30%. Frequency of abandonment

bobwhite. She was observed moving into the nest following a recess event, then promptly ran out of the nest carrying an egg, and continued out of the camera view. On the previous day, this bird had been observed defending her nest against attack by ants. The final observation of a bobwhite carrying an egg was a female bobwhite that emerged from her nest carrying an egg and flew away with it in her beak. In all observations, the bobwhite appeared to be carrying the egg with the lower mandible inserted into a hole in the egg. Based on camera observations, it could not be determined if the bobwhite created the hole or the egg had previously been damaged. Among predation events, we also identified temporal differences among predator species relative to incubation period. For the two groups most involved in partial predation events, we observed nonoverlapping 95% confidence intervals; mean day of incubation for predation events by snakes was 11.8 (95% CI: 8.9–14.7), whereas for ants, mean day of depredation was 17.8 (95% CI: 15.0–20.6). Although the 95% confidence intervals overlap, there is a trend toward more eggs remaining after ant predation events than after snake events. Average percent of eggs remaining after an ant depredation was 66.8% (95% CI: 50.2–83.4%) compared to 48.6% (95% CI: 39.5– 57.7%) remaining following snake depredations. The Hosmer–Lemeshow goodness-of-fit statistic for the global model indicated logistic regression was an adequate fit for the data set (P ⫽ 0.26). Data demonstrated overdispersion (c^ ⫽ 1.42); therefore an adjustment was made to correct the overdispersion and an additional scaling parameter was added to each of the models. All but two models possessed at least some weight, with 95% of weight carried by 13 of the models (Table 13.2). The best approximating model for predicting bobwhite abandonment following partial clutch loss included the predictors of age, date of incubation, and percentage of eggs remaining, while the next best fitting model included only date of incubation and percentage of eggs remaining (Table 13.2). Percentage of eggs remaining following partial clutch loss and date of incubation were the variables that appeared to best describe the probability of bobwhite abandonment following a partial depredation (Table 13.2). While the scaled odds ratios had 95% confidence intervals

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0

(11) (12)

(22)

1–7

8–15

16–23

Day of incubation

Figure 13.2. Frequency of nest abandonment (± 95% confidence intervals) by attending Northern Bobwhites following partial depredation events by day of incubation. Scalar unit of analysis was 7 days.

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Ribic, Thompson, and Pietz

TABLE 13.2 AICc model selection for 24 candidate models examining cues bobwhite use in deciding whether to abandon a nest following partial clutch loss.

⌬AICc

Model

K

Dev

wi

Age ⫹ DOI ⫹ per_eggs

5

18.92

0.00

0.293

DOI ⫹ per_eggs

4

22.34

0.76

0.200

Age ⫹ Sex ⫹ DOI ⫹ per_eggs

6

17.92

1.76

0.122

per_eggs

3

26.83

2.81

0.072

Age ⫹ DOI

4

24.67

3.04

0.064

Age ⫹ per_eggs

4

24.80

3.28

0.057

DOI

3

28.90

4.83

0.026

Age

3

28.90

4.86

0.026

Constant (intercept only)

1

31.45

5.10

0.023

Sex ⫹ per_eggs

4

26.80

5.22

0.022

Age ⫹ DOI ⫹ TBS

5

24.60

5.51

0.019

Age ⫹ Sex ⫹ DOI

5

24.64

5.55

0.018

Sex

3

30.65

6.57

0.011

Sex ⫹ DOI

4

28.31

6.63

0.011

Age ⫹ Sex

4

28.77

7.14

0.008

DOI ⫹ TBS

4

28.90

7.23

0.008

TBS

3

31.35

7.28

0.008

Age ⫹ Sex ⫹ DOI ⫹ TBS

6

24.58

8.16

0.005

Pred ⫹ per_eggs ⫹ DOI

5

22.13

8.70

0.004

Pred ⫹ per_eggs

4

26.42

10.12

0.002

Pred

3

31.07

11.91

0.001

Pred ⫹ DOI

4

28.74

12.21

0.001

Age ⫹ Sex ⫹DOI ⫹ TBS ⫹ Pred ⫹ per_eggs

8

17.44

14.14

0.000

Age ⫹ Sex ⫹ Pred

5

28.70

15.10

0.000

NOTE: Predictor variables are age and sex of incubating bobwhite, timing in the breeding season (TBS), day of incubation (DOI) when the depredation event occurred, percent of eggs (per_eggs) remaining, and predator (Pred).

DISCUSSION Even with our large sample of nests monitored, we demonstrate that investigation of specific behaviors in nesting studies are still difficult to accomplish even with video monitoring. Our findings may not be as strong as we would like about the relationship of specific cues to bobwhite abandonment following partial depredations, but there have not been any other camera studies to our knowledge focusing on partial depredations in ground-nesting birds with indeterminate clutches. Our results suggest that some cues

deserve further consideration and examination and are better than the intercept-only model. Our findings suggest that bobwhites may use multiple cues to assess the value of a clutch and reproductive decisions following partial depredation, as no single cue which we examined was driving their decisions. Of the predictors we examined, day of incubation and percentage of eggs remaining appear to play a role in the bobwhite’s decision to either abandon the nest and try to renest or to salvage the effort invested in the partially depredated nest. Researchers studying waterfowl have found

PARTIAL DEPREDATION AND BOBWHITE

167

TABLE 13.3 Model-averaged parameter estimates for bobwhite abandonment following partial clutch loss and their associated scaled odds ratios.

95% CI for scaled odds ratio Parameter INTERCEPT AGE

Estimate

SE

3.663

3.280

⫺2.264

1.769

Odds ratio

Unit scalar

Scaled odds ratio

0.104

1

0.104

0.003

3.331

Lower

Upper

SEX

⫺1.032

2.042

0.356

1

0.356

0.007

19.511

DOI

⫺0.199

0.114

0.820

7 days

0.249

0.052

1.184

TBS

0.002

0.015

1.002

7 days

1.012

0.821

1.247

UNKNOWN

0.346

1.575

1.413

1

1.413

0.064

30.948

SNAKE

0.088

1.566

1.092

1

1.092

0.051

23.505

0.843

0.006

114.263

0.319

0.061

1.665

PREDATOR:

MAMMAL

⫺0.171

2.505

0.843

1

PER_EGGS

⫺0.038

0.028

0.963

30%

NOTES: Odds ratios⬎1.0 indicate a positive response relative to a unit scalar change; ⬍1.0 is a negative response. Scaled odds ratios represent the likelihood of change relative to a biologically significant unit change. Predator estimates are relative to ants.

similar results. Ackerman and Eadie (2003) found that both day of incubation and the proportion of eggs remaining were important predictors in Mallard (Anas platyrhynchos) nest abandonment. Hall (1987) also observed higher nest abandonment at mallard nests with a greater proportional clutch loss. Although waterfowl are also ground nesters with indeterminate clutches, parental investment is likely quite different from bobwhites because of other life history traits. Specifically, the attending bobwhite’s age appeared to carry some weight. Given the short lifespan and high annual mortality that bobwhites experience (Stoddard 1931, Brennan 1999), a bobwhite might be more likely to take greater risks in their second breeding season than their first because there may be limited opportunities for future offspring (Montgomerie and Weatherhead 1988). Interestingly, most predation events by ants occurred later in incubation but resulted in a greater proportion of the clutch remaining. Fire ants were unable to directly access eggs unless they were damaged or hatching. Since many of the attempts occurred later in incubation, but not always at hatch, only a few eggs were typically lost due to lack of access to the egg. When the incubating bobwhite is present at the nest, it will aggressively defend against ants within the nest (Burnam 2008). Based upon our camera observations, we believe that eggs may be damaged during defense or as a result of predator disturbance. This may result in access to the egg by ants and ultimately partial clutch loss. However, the incubating bobwhite, as we observed, may be removing the damaged egg to increase the probability of success for the remaining eggs in the clutch (Kemal and Rothstein 1988). Studies conducted on partial depredations traditionally use a decrease in clutch size (Ackerman and Eadie 2003; Ackerman et al. 2003a, 2003b) as evidence of partial predation events. However, our camera observations suggest that not all clutch loss is the direct result of predation, but rather has been suggested to be a response to damaged or infertile egg(s) (Robinson and Robinson 2001). Our lack of strong relationships between the cues used in our study and bobwhite abandonment may also suggest that other cues may be driving bobwhite parental care decisions

relative to partial clutch loss. For example, bobwhites are persistent renesters and often hatch multiple broods within a breeding season. Investments in terms of how many previous attempts have been made and the success of those attempts may influence the risks a bobwhite is willing to take following partial predations events at current nests. Evaluation of predation risk may be influenced by specific features associated with nesting habitat, such as nest location on the landscape and concealment. Ackerman et al. (2003b) also suggested that clutch size attributes can be examined in several ways. For example, the initial value of eggs or the absolute number of eggs remaining may better reflect how a bird evaluates reproductive investment and potential gains (Ackerman et al. 2003b). In assessing recruitment and other parameters relative to population dynamics of bobwhites, our results suggest that traditional approaches using nesting success where at least one egg hatches does not account for the amount of production gained or lost as a result of partial depredations (also see Pietz et al., chapter 1, this volume), and additional information related to egg success would provide additional information on production (Ackerman et al. 2003a). The relative contribution of particular species to both full and partial depredations, as well as temporal factors such as predation events during early or late incubation, lead to different production gains that require more detailed measures. Future research needs to address production and the specific role of predators with respect to partial clutch loss at bobwhite nests. In summary, our findings suggest that bobwhites use multiple cues to assess the value of a current clutch following partial depredations. The proportion of the clutch lost appears to be an important factor in conjunction with clutch age and to some extent the age of the attending bobwhite. Partial depredations are important from both an applied and a theoretical perspective, and there is a need for a better understanding of the role they play in production and reproductive decisions of avian species. In addition, our camera system represented a major opportunity to assess behaviors of bobwhites resulting from predation events that were previously only available through anecdotal evidence.

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ACKNOWLEDGMENTS We would like to thank the many technicians and interns who radio-tracked bobwhites, changed batteries and tapes in our cameras, and watched hours of video footage to identify nest predators. We appreciate comments by C. J. Ribic, P. A. Pietz, and three anonymous reviewers on earlier versions of this manuscript. Funding was provided by a Direct Congressional Appropriation, The University of Georgia Graduate School, the Warnell School of Forestry and Natural Resources, McIntireStennis Projects GEO 100 and 136, the Albany Quail Project, and Tall Timbers Research Station and Land Conservancy, Inc. Additional funding was provided by the Northeast Georgia Chapter of Quail Unlimited and the American Association of University Women.

LITERATURE CITED Ackerman, J. T., and J. M. Eadie. 2003. Current versus future reproduction: an experimental test of parental investment decisions using nest desertion by Mallards (Anas platyrhynchos). Behavioral Ecology and Sociobiology 54:264–273. Ackerman, J. T., J. M. Eadie, D. L. Loughman, G. S. Yarris, and M. R. McLandress. 2003a. The influence of partial clutch depredation on duckling production. Journal of Wildlife Management 67:576–587. Ackerman, J. T., J. M. Eadie, G. S. Yarris, D. L. Loughman, and M. R. McLandress. 2003b. Cues for investment: nest desertion in response to partial clutch depredation in dabbling ducks. Animal Behaviour 66:871–883. Anderson, D. R. 2008. Model based inference in the life sciences: a primer on evidence. Springer, New York, NY. Barash, D. P. 1975. Evolutionary aspects of parental behavior: distraction behavior of the Alpine Accentor. Wilson Bulletin 87:367–373. Brennan, L. A. 1999. Northern Bobwhite (Colinus virginianus). Birds of North America No. 397, Academy of Natural Sciences, Philadelphia, PA. Bruning, D. F. 1973. The Greater Rhea chick and egg delivery route. Natural History 82:68–75. Burger, L. W., Jr., M. R. Ryan, T. V. Dailey, and E. W. Kurzejeski. 1995. Reproductive strategies, success, and mating systems of Northern Bobwhite in Missouri. Journal of Wildlife Management 59:417–426. Burnam, J. S. 2008. Monitoring patterns of nest defense and incubation behavior in Northern Bobwhites (Colinus virginianus) using continuous video. M.S. thesis, The University of Georgia, Athens, GA. Burnham, K. P., and D. R. Anderson. 2002. Model selection and multimodel inference: a practical information-theoretic approach. Second edition. Springer-Verlag, New York, NY.

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Byers, C. R., R. K. Steinhorst, and P. R. Krausman. 1984. Clarification of a technique for analysis of utilization-availability data. Journal of Wildlife Management 48:1050–1053. Choate, J. S. 1967. Factors influencing nesting success of eiders in Penobscot Bay, Maine. Journal of Wildlife Management 31:769–777. Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North American north of Mexico.Herpetological Circular No. 37. Society for the Study of Amphibians and Reptiles, Salt Lake City, UT. ⬍http://www.ssarherps.org/ pdf/HC_37_6thEd.pdf⬎ (22 September 2010). Gochfeld, M. 1984. Antipredation behavior: aggressive and distraction displays of shorebirds. Pp. 289– 377 in J. Burger and B. L. Olla (editors), Shorebird breeding behavior and populations. Plenum Press, New York, NY. Hall, M. R. 1987. Nesting success in Mallards after partial clutch loss by predators. Journal of Wildlife Management 51:530–533. Hosmer, D., and S. Lemeshow. 1989. Applied logistic regression. Wiley and Sons, New York, NY. Kemal, R. E., and S. I. Rothstein. 1988. Mechanisms of avian egg recognition: adaptive responses to eggs with broken shells. Animal Behaviour 36:175–183. Lariviere, S., and F. Messier. 1997. Characteristics of waterfowl nest depredations by the striped skunk (Mephitis mephitis): can predators be identified from nest remains? American Midland Naturalist 137:393–396. Lebreton, J. D., K. P. Burnham, J. Clobert, and D. R. Anderson. 1992. Modeling survival and testings biological hypotheses using marked animals: a unified approach with case studies. Ecological Monographs 62:67–118. Mallory, M. L., D. K. McNicol, R. A. Walton, and M. Wayland. 1998. Risk-taking by incubating Common Goldeneyes and Hooded Mergansers. Condor 100:694–701. Montgomerie, R. D., and P. J. Weatherhead. 1988. Risks and rewards of nest defence by parent birds. Quarterly Review of Biology 63:167–187. Rader, M. J., T. W. Teinert, L. A. Brennan, F. Hernandez, N. J. Silvy, and X. B. Wu. 2007. Identifying predators and nest fates of bobwhites in southern Texas. Journal of Wildlife Management 71:1626– 1630. Ricklefs, R. E. 1969. An analysis of nesting mortality in birds. Smithsonian Contribution to Zoology 9:1–48. Ricklefs, R. E. 1973. Ecology. Chiron Press, New York, NY. Robinson, W. D., and T. R. Robinson. 2001. Observations of predation events at bird nests in central Panama. Journal of Field Ornithology 72:43–48.

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Rosene, W. 1969. The bobwhite quail, its life and management. Rutgers University Press, New Brunswick, NJ. Sisson, D. C., H. L. Stribling, and D. W. Speake. 2000. Effects of supplemental feeding on home range size and survival of Northern Bobwhites in South Georgia. Proceedings of the National Quail Symposium 4:128–131. Sisson, D. C., T. M. Terhune, H. L. Stribling, J. Sholar, and S. Mitchell. 2009. Survival and cause of mortality of Northern Bobwhite (Colinus virginianus) in the southeastern USA. Pp. 467–478 in S. B. Cederbaum, B. C. Faircloth, T. M. Terhune, J. J. Thompson, and J. P. Carroll (editors), Gamebird 2006: Quail VI and Perdix XII, 31 May–4 June 2006, Warnell School of Forestry and Natural Resources, Athens, GA. Sjoberg, G. 1994. Factors affecting nest defence in female Canada Geese Branta canadensis. Ibis 136:129–135.

Staller, E. L., W. E. Palmer, J. P. Carroll, R. P. Thornton, and D. C. Sisson. 2005. Identifying predators at Northern Bobwhite nests. Journal of Wildlife Management 69:124–132. Stoddard, H. L. 1931. The bobwhite quail: its habits, preservation and increase. Charles Scribner’s Sons, New York, NY. Szekely, T., J. N. Webb, A. I. Houston, and J. M. McNamara. 1996. An evolutionary approach to offspring desertion in birds. Current Ornithology 13:271–330. Trivers, R. L. 1972. Parental investment and sexual selection. Pp. 136–179 in B. Campbell (editor), Sexual selection and the descent of man. Aldine Publishing Company, Chicago, IL. Williams, G. E., and P. B. Wood. 2002. Are traditional methods of determining nest predators and nest fates reliable? An experiment with Wood Thrushes (Hylocichla mustelina) using miniature video cameras. Auk 119:1126–1132.

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CHAPTER FOURTEEN

Identification of Sprague’s Pipit Nest Predators Stephen K. Davis, Stephanie L. Jones, Kimberly M. Dohms, and Teslin G. Holmes

Abstract. Nest predation is the primary factor influencing grassland songbird reproductive success. Understanding factors driving spatial and temporal variation in nest survival requires that we identify the primary nest predators and factors influencing predator abundance and behavior. Predation events are rarely witnessed, and the identification of nest predators is inferred, often incorrectly, from nest remains or observations of potential predators. We used video photography to identify predators of Sprague’s Pipit (Anthus spragueii) nests in Saskatchewan and Montana. We monitored 60 nests in Saskatchewan and 11 nests in Montana and documented at least ten different species preying upon eggs and nestlings. Northern Harrier (Circus cyaneus) and thirteenlined ground squirrel (Ictidomys tridecemlineatus) were the most common nest predators documented on videotape, along with mouse

(Peromyscus spp.), vole (Microtus spp.), deer (Odocoileus spp.), striped skunk (Mephitis mephitis), coyote (Canis latrans), Black-billed Magpie (Pica hudsonia), Western Meadowlark (Sturnella neglecta), and gartersnake (Thamnophis spp.). Most predation events occurred during the nestling stage and primarily during the day, potentially due to the increased activity of adults feeding young and of the nestlings begging for food. The diverse predator communities documented destroying grassland songbird nests presents many challenges for land managers attempting to increase reproductive success of Sprague’s Pipits and other priority grassland birds.

G

(Winter 1999, Davis and Sealy 2000). Predation is often the primary cause of nest failure (Davis 2003, Jones et al. 2010). Understanding factors driving spatial and temporal variation in nest survival requires that we identify nest predators and factors influencing predator abundance and

rassland species experience higher rates of nest predation than birds nesting in forest and wetland habitats (Martin 1993). Although nest success can be highly variable, some studies show predation rates for grassland songbird nests to be as high as 50–70%

Key Words: grassland birds, nest predation, nest predators, Northern Harrier, Sprague’s Pipit, thirteen-lined ground squirrel, video monitoring, Western Meadowlark.

Davis, S. K., S. L. Jones, K. M. Dohms, and T. G. Holmes. 2012. Identification of Sprague’s Pipit nest predators. Pp. 173–182 in C. A. Ribic, F. R. Thompson III, and P. J. Pietz (editors). Video surveillance of nesting birds. Studies in Avian Biology (no. 43), University of California Press, Berkeley, CA.

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behavior. Such information may allow land managers to prescribe appropriate land use and management regimes that are beneficial to grassland nesting birds (Phillips et al. 2003, Thompson and Ribic, chapter 2, this volume). Predation events are rarely witnessed and identification of nest predators is inferred, often incorrectly, from nest remains or observations of potential predators (Larivière 1999, Pietz and Granfors 2000a, Williams and Wood 2002). Identification of nest predators has previously relied on artificial nests (Davison and Bollinger 2000). Although these experiments allow researchers to acquire large sample sizes and possibly identify predator guilds (e.g., avian, small mammal, mid-sized mammal), species identification is difficult and there are potential biases associated with artificial nests (Major and Kendal 1996, Thompson and Burhans 2004). Video monitoring has become an important method of studying nesting behavior and provides a reliable means of identifying nest predators and accurately assessing nest fate (Pietz and Granfors 2000a, Sanders and Maloney 2002, Renfrew and Ribic 2003). Unlike opportunistic field observations, video monitoring is not biased by time of day or detectability of predators. We used video photography to identify predators of Sprague’s Pipit (Anthus spragueii) nests in Saskatchewan and Montana. Sprague’s Pipit (hereafter pipit) is a ground-nesting passerine of the northern mixed-grass prairie. Pipit populations have declined dramatically (Sauer et al. 2008), and the species is listed as threatened in Canada (COSEWIC 2000) and has been recommended for listing in the United States (USFWS 2010). Like most grassland passerines, reproductive success appears to be influenced primarily by nest predation (Davis and Sealy 2000, Davis 2003, Jones and Dieni 2007, Jones et al. 2010). Davis and Fisher (2009) witnessed thirteen-lined ground squirrel (Ictidomys tridecemlineatus) and Northern Harrier (Circus cyaneus) predation on radio-tagged pipit nestlings and fledged juveniles, but it is unknown to what extent these species are important nest predators. Our objectives were to (1) determine which animals prey upon Sprague’s Pipit eggs and young, (2) determine the extent to which pipit nest predator communities overlap in two geographic regions, and (3) describe the behaviors of pipits and nest predators to assist researchers interested in monitoring pipit reproductive success and determining nest fate.

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METHODS Study Site Fieldwork was conducted at the north end of Last Mountain Lake in south-central Saskatchewan, Canada (51°48⬘N, 107°57⬘W), during 2005–2008 and Bowdoin National Wildlife Refuge (NWR) in north-central Montana, U.S. (48°24⬘N, 107°39⬘W), during 2002–2007. Study sites consisted of four native mixed-grass prairie pastures and four planted hay fields in Saskatchewan and four native mixed-grass prairie sites in Montana. Detailed site descriptions are provided in Davis (2009) and Davis and Fisher (2009) for Saskatchewan sites and Jones and Dieni (2007) and Jones et al. (2010) for Montana sites. Saskatchewan pastures were grazed lightly by cattle throughout the breeding season, and haying did not occur until early August. Bowdoin NWR has not been grazed by cattle for ⱖ26 years, and prescribed spring burning occurred on a different site in each of 2000, 2004, and 2007. Nest Searching and Monitoring We conducted fieldwork between May and August, primarily from 06:00 to 14:00 Mountain Daylight Time (MDT) in Saskatchewan and throughout the day in Montana. Nest searches were conducted by systematically dragging a 25-m nylon rope weighted with aluminum and tin cans through fields to flush incubating birds off nests (Davis 2003). We also located nests using behavioral observations and fortuitously while conducting other activities on the sites. We recorded the location of each nest with a hand-held Global Positioning System unit and marked nests with colored surveyor flags 5 m south and north of the nest (Saskatchewan) and with a strip of plastic flagging on the ground approximately 2.5 m on either side of the nest (Montana). Camera Monitoring In Saskatchewan, we installed small (37 mm ⫻ 86 mm) color, infrared video cameras (National Electronics Bullet C/IR Low Light Color Bullet Camera, Brookvale, NSW, AU) mounted on small metal stands (70 mm) at randomly selected pipit nests. We installed cameras during early to midincubation (two at day 3 and one at day 6) and during the nestling stage (one each at day 3 and NO. 43

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day 7) in 2004 and 2005 as part of a pilot project. In 2006 and 2007, we installed cameras at nests from mid- to late incubation (8.7 ⫾ 3.1SD days; n ⫽ 32) or shortly after hatching (2.3 ⫾ 1.7 days; n ⫽ 7) as part of a nestling provisioning study (Dohms 2009). Cameras were removed from the nesting area when the young fledged the nest or the nest failed. In 2008, we installed cameras during early incubation as part of an incubation attentiveness study (4.7 ⫾ 1.5SD days; n ⫽ 16; Donald 2009) and videotaped nests until hatching or the nest failed. We covered each camera with local vegetation, and set cameras 30–50 cm from the nest entrance to minimize disturbance. Cameras were connected via coaxial cable (RG6) to a time-lapse 24-hr videocassette recorder (VCR, Sanyo SRT 2400DC or 4040DC, Concord, ON) and 12-V, deep-cycle marine battery located at least 50 m from the nest and concealed beneath a vented box. The VCR time-lapse feature allowed 24 hr of activity to be recorded on 8-hr videotapes at about 4–5 images/sec. We changed videotapes every 24 hr and batteries every 48 hr or when they had discharged. Cameras recorded nests regardless of weather conditions, but we did not install cameras when it was raining or when temperatures were ⬍5⬚C to minimize impacts on nesting females, eggs, or young. We checked nests using a hand-held color video monitor when changing videocassettes and every 2–3 days as part of the regular nest-monitoring schedule. In Montana, we used the miniature video camera systems described in Pietz and Granfors (1998) on four nest monitoring sites (Jones et al. 2010). Methodologies were similar to those used in Saskatchewan except that cameras were deployed at nests as early in the incubation period as possible and where surrounding vegetation was high enough to conceal the camera. We used the logistic exposure method (Shaffer 2004) to estimate daily nest survival for nests with and without cameras and for video-monitored nests in the incubation and nestling stages. We considered two separate models, each with only the categorical covariates of interest (camera vs. non-camera and incubation vs. nestling stage). For the camera nest comparison, we also restricted our analysis to nests that were ⬎6 days into incubation because most of our camera nests were monitored after the sixth day of incubation (see below). We conducted analyses only for nests in Saskatchewan because of the small sample of

video-monitored nests in Montana. We estimated cause-specific daily rates of predation, abandonment, and failures due to other causes using a multinomial logistic regression and an interceptonly model; this model estimates an intercept for each class of failure, which represents the daily probability of failure to that cause. For losses to more specific causes and specific predators, we simply report the frequency of events because the number of events was too small for more rigorous model-based approaches.

RESULTS Saskatchewan We monitored 60 nests with cameras in Saskatchewan; 20 nests successfully fledged at least one host young, three nests were abandoned (two nests within two days and one nest ⬎1 week after setting up the camera), eight nests failed due either to extended periods of cool, wet weather (n ⫽ 5), Brown-headed Cowbird (Molothrus ater) parasitism (n ⫽ 1), or infertile eggs (one female incubated for at least 21 days before abandoning the clutch), and one nest was buried by a northern pocket gopher (Thomomys talpoides). The fate of one nest could not be determined because vegetation blocked the camera during the latter part of the nesting period. A total of 27 nests used for video monitoring were predated, with 17 predation events captured on video. Five nests were depredated after the camera system was removed, and the remainder failed to document predators because of technical problems (e.g., dead batteries or faulty equipment) and cattle knocking over one of the cameras. At least seven species were recorded preying upon pipit nests (Table 14.1). Four nests were preyed upon during the incubation period and the remainder (n ⫽ 13) during the nestling period. The number of days that nests were monitored by cameras during the incubation period was greater than the nestling period (370 vs. 303 exposure days). However, 89% of incubation exposure days occurred after the sixth day of incubation. Predation events occurred throughout the 24-hr time period, but were most prevalent during daylight hours (Table 14.2). Small mammals were the most common predator of pipit nests in Saskatchewan (Table 14.1). A vole (Microtus spp.) mutilated five 1-day-old nestlings, but it was not clear if the young were alive at the time since the female had been absent from

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175

TABLE 14.1 Predators recorded on video preying upon Sprague’s Pipit nests during the incubation and nestling stages in Saskatchewan (2005–2008) and Montana (2002–2007).

Saskatchewan Predator Thirteen-lined ground squirrel (Ictidomys tridecemlineatus)

Incubation

Nestling

1

5

Deer (Odocoileus spp.) Striped skunk (Mephitis mephitis) Coyote (Canis latrans)

1 2

2 1

1 2

Northern Harrier (Circus cyaneus)

2

Western Meadowlark (Sturnella neglecta)

1

Gartersnake (Thamnophis spp.)

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3

2

Black-billed Magpie (Pica hudsonia)

the nest for nearly 8 hr and was never recorded thereafter. Thirteen-lined ground squirrels were responsible for six of 17 predation events, making it the most common predator recorded on video; five of these events occurred during the nestling stage (Table 14.1). The single egg-predation event occurred in the evening (Table 14.2) and involved a ground squirrel consuming all four eggs (contents and shells) outside the nest in a 3-min period. The adult pipit returned to the nest 3 min later and removed the remaining egg shells, entering and departing the nest for 39 min before abandoning. Behavior of ground squirrels depredating nestlings varied. In two of five cases the ground squirrel removed a single young; both nestlings were 5–6 days old. In one of these cases a striped skunk (Mephitis mephitis) ate the remaining three young two days later (Table 14.2). In the other three cases, multiple young were preyed upon. At one nest, 42 min elapsed between leaving with the first young and retrieving a second young. A ground squirrel visited this nest the following morning and removed the third of five nestlings (Table 14.2). At another nest, a ground squirrel removed a nestling during the late morning and again around noon the following day. The next day, a ground squirrel arrived in mid-afternoon and removed the remaining three young from this nest over a 20-min period. The last ground squirrel predation event involved the killing (chewing) of at least three of

Nestling

1

Vole (Microtus spp.) Mouse (Peromyscus spp.)

Montana

five young in one visit. The predator removed one young from the nest at the end of the first visit then returned 17 min later and removed a headless body from the nest. Six min later the adult pipit began to remove two dead nestlings and a decapitated head from the nest. The predator returned 2.5 hr later to take the remaining nestling. At three nests, a ground squirrel was attacked by an adult pipit, but eventually managed to remove at least one young from the view of the camera. In all cases of partial predation, adults continued to feed remaining nestlings. Before abandoning their nests after complete depredations, adults continued to return to empty nests for a period of 12 min to 6 hr 12 min after the last ground squirrel visit. Nestling ages at the time of ground squirrel predation ranged from shortly after hatch to fledging age (12 days), with most nestlings being five days or older (Table 14.2). All other predators documented on video consumed the entire nest contents. Deer (Odocoileus spp.) consumed two clutches of eggs in ⬍20 sec and two nests with nestlings in ⬍53 sec, and a coyote (Canis latrans) consumed eggs in 22 sec. Black-billed Magpies (Pica hudsonia) made multiple visits to the same nests over a 9–12-min period, and Northern Harriers removed five nestlings over a 3 hr 32 min period at one nest and four nestlings in a 4-min period at a second nest. Daily nest survival rates were similar between the incubation (0.982; 95% CI ⫽ 0.969–0.989) and NO. 43

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TABLE 14.2 Time of day (MDT) predators appeared in view of the camera (Arrival Time), age in days of eggs or nestlings at time of predation (Age), and amount of time passed between attending adult departure from the nest and arrival of nest predators (Depart) in Saskatchewan (2005–2008) and Montana (2002–2007).

Snake

Avian

Small mammal

Arrival time

Depart (sec)

Age (days)

Arrival time

Depart (sec)

Species

Age (days)

Arrival time

Depart (sec)

20:11

60

13

07:45

210

BBMA

11

12:54

367

BBMA

2

08:02

Mid–large sized mammal

Species

Age (days)

Arrival time

Depart (sec)

Species

Age (days)

13-linedC1

7

00:53

3

SkunkE3

7

0

C2

13-lined

8

03:43

4

Coyote

5*

13-lined

D1

6

04:08

6

Deer

12

13-linedD2

7

23:42

49

Deer

2

8

20:46

67

Deer

11*

11

00:56

19

Deer

11*

09:10

—

16:02

677

NOHA

10

10:41

167

13:59

266

NOHA

12

11:53

61

21:08

360

NOHA

7

15:44

411

17:28

22

NOHA

7

09:29

446

13-lined

11:43

866

NOHA

4

13-lined

10:32

1,380

A1

9

13-lined

D3

1

20:43

420

15:43

523

06:14

24

WEMEA2

10

18:54

417

13-lined

19:04

613

B1

WEME

8

00:39

7,487

Mouse

10

07:49

904

WEMEB2

9

22:38

28,258

Vole

1

WEME

13-lined

E1

5 8*

NOTES: Superscripts sharing the same letter but with different numbers indicate the same nest predated on different days. Species include Black-billed Magpie (BBMA), Northern Harrier (NOHA), Western Meadowlark (WEME), thirteen-lined ground squirrel (13-lined), and striped skunk (Skunk). Asterisk indicates incubation day; all other predation events occurred during the nestling period.

nestling stages (0.964; 95% CI ⫽ 0.946–0.977) of video-monitored nests. Furthermore, nest survival was similar between camera (0.855; 95% CI ⫽ 0.803–0.849) and noncamera nests (0.844; 95% CI ⫽ 0.813–0.871), even when restricting the comparison to nests that were older than the sixth day of incubation (0.845; 95% CI ⫽ 0.789–0.887 vs. 0.849; 95% CI ⫽ 0.815–0.877, respectively). We estimated cause-specific failure rates based on 674 camera observation days, 22 predation events, 3 abandonments, and 8 losses to other causes. The daily probability of loss to predation (0.033; 95% CI ⫽ 0.021–0.049) was greater than losses to abandonment (0.005; 95% CI ⫽ 0.001–0.012) and other causes (0.012; 95% CI ⫽ 0.005–0.022). Montana We monitored 11 pipit nests with cameras in Montana and documented seven nests being preyed upon by four species (Table 14.1). All predation events involved nestlings and occurred during daylight hours, except for the mouse predation, which occurred during the night (Table 14.2). Overall, nestlings were estimated to be 7–10 days old when they were taken from the nest. Northern Harriers were responsible for three of seven depredated nests; the harriers consumed all the nestlings at each nest. At two nests, a harrier consumed all four nestlings over a 5-min period. At the third nest, a harrier consumed three of the nestlings on the first visit and 1 min later revisited the nest and consumed the fourth nestling. In the first nest (above), the nest was empty by 21:19 yet adult pipits continued to bring food until 22:02 and again at 06:04 the following morning; no further visits by adult pipits were recorded at the nest. In the second case, adult pipits continued to bring food to the empty nest and periodically “brood” for at least 3 hr before the camera stopped recording. Details of continued adult attendance at the third nest could not be described because vegetation obscured the video-recording. Western Meadowlarks (Sturnella neglecta) preyed upon two of seven nests. At one nest, a meadowlark removed and consumed a single nestling between 20:43 to 20:48. The meadowlark visited the nest 36 min later, removed the second nestling, and pecked at the heads of the remaining two nestlings; 3 min later the meadowlark removed a third nestling from the nest. Adult pipits visited the nest during the night, and at 06:14 the following morning 178

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a meadowlark removed the last nestling from the nest, again pecking at its head. The meadowlark left when an adult pipit arrived with food at 06:18 and the meadowlark returned again at 07:44, followed shortly by the adult pipit carrying food. No pipit adults were observed again, but a meadowlark visited the nest at 08:02. At the second pipit nest depredated by a meadowlark, a Richardson’s ground squirrel (Urocitellus richardsonii) investigated the camera (ignoring the nest) at 17:35, after which a meadowlark arrived at 19:04. The meadowlark pulled two of four nestlings from the nest, and continued to peck nestlings that were outside the nest when revisiting the nest on two occasions over a 20-min period. The meadowlark left the nest when an adult pipit arrived to feed the two nestlings remaining in the nest. The meadowlark returned at 07:34 the next morning and killed another nestling. The adult pipit arrived with food at 07:49, when the last nestling was observed alive. Pipits continued to deliver food until 08:00, when the last nestling died, presumably of injuries. Deaths of the nestlings were presumed when their movements stopped. Adults continued to deliver food for 1 hr 4 min, with no further activity for another 1 hr 20 min, when the camera stopped recording. The mouse (Peromyscus spp.) predation event involved a mouse entering the nest at 00:39 and killing four of the five nestlings over a 6-min period. A mouse returned the next morning at 04:19, staying at the nest for 6.8 min. The adult pipit first brought food to the nest at 05:58 and the pipits continued to visit the nest until the last nestling died by 11:34, probably due to injuries sustained earlier. During incubation, a gartersnake (Thamnophis spp.) visited a nest for 3.7 min without removing an egg. The same nest was visited 13 days later by a gartersnake entering the nest at 20:11, forcing the fledging of three 13-day-old nestlings. The gartersnake grabbed the fourth nestling by the leg and removed it from the nest at 20:14. A gartersnake returned to the nest at 22:06 and remained for 4 min. Adult pipits were recorded back at the nest at 05:00 the next morning carrying food; this behavior continued until 07:49.

DISCUSSION Video-recording technology allowed us to identify diurnal and nocturnal predators of Sprague’s Pipit nests in Saskatchewan and Montana. Until now it was unknown which species were NO. 43

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predators of pipit nests, although mammals, snakes, and raptors were suspected (Robbins and Dale 1999). We documented at least ten different species preying upon pipit nests. Our results, combined with those reported by Davis and Fisher (2009), indicate that thirteen-lined ground squirrels and Northern Harriers are common predators of pipit nests in our study areas. Although video studies likely underestimate the number of predator species taking songbird nests due to possible avoidance of camera equipment by some species (Pietz and Granfors 2000a, Pietz at al., chapter 1, this volume), evidence is mounting that grassland songbird predator communities are diverse, and small mammals, particularly thirteen-lined ground squirrels, are common nest predators (Schaeff and Picman 1988, Pietz and Granfors 2000a, Renfrew and Ribic 2003, Ribic et al., chapter 10, this volume). Our results also support past studies showing that video-camera systems do not reduce nest survival rates of camera-monitored nests (Pietz and Granfors 2000a, Renfrew and Ribic 2003, Powell et al., chapter 5, this volume). Our video cameras also captured other seemingly uncommon predators implicated in previous video studies such as deer, mice, and voles (Pietz and Granfors 2000b, Renfrew and Ribic 2003). All are commonly encountered in our study areas and likely take more nests than wildlife biologists realize (Pietz and Granfors 2000b), although commonly suspected species such as coyote, snake, and striped skunk were also captured on video. We documented only one canid predator in our study, despite having an active coyote den on one of our study plots in Saskatchewan. Furthermore, few canids were recorded on cameras in North Dakota (Pietz and Granfors 2000a), even though both red fox (Vulpes vulpes) and coyote are common predators of waterfowl nests (Sargeant et al. 1993). These canids may not target passerine nests as they do waterfowl nests because of the relatively low reward and low probability that a flushed passerine is associated with a nest (A. B. Sargeant, pers. comm.). Canids may also avoid camera nests because they are wary of novel things in their environment (Hernandez et al.1997) and of human scent (MacIvor et al. 1990). Furthermore, wild canids are typically “hunted” outside protected areas in our region and may avoid our study sites, particularly during the day, when human activity is the greatest. Although similar reasoning could be made for deer, unlike

canids, deer appear to be a relatively common predator of grassland songbird nests (Pietz and Granfors 2000b). The relatively large number of predation events attributed to deer may simply be a function of their abundance, or, unlike canids, they may be attracted to novel objects in their environment such as nest markers and video equipment. We recorded two cases of predation by Western Meadowlarks in Montana, which was unexpected given our small sample size. We also recorded a meadowlark visiting a nest in Saskatchewan, but the bird simply investigated the nest area and then departed. Meadowlarks are known to prey upon eggs and young and to scavenge carcasses (Creighton and Porter 1974, Davis and Lanyon 2008). Meadowlarks killed the nestlings at two nests in our study but did not consume all individuals, even when they returned to the nest the following day. Nest predation may represent opportunistic feeding for this species or some mechanism to reduce competition from neighbors (Creighton and Porter 1974). Our results suggest that predation risk is greatest during the day, especially during the nestling period. Approximately 72% of our recorded predation events occurred during daylight hours. The importance of nocturnal and diurnal predators likely varies according to local predator guilds. For example, Pietz and Granfors (2000a) reported that most grassland bird nests were taken by diurnal predators, whereas Renfrew and Ribic (2003) documented a greater proportion of nocturnal predation events; likely reflecting the prevalence of thirteen-lined ground squirrels and mid-sized mammals in their respective study areas. Over 83% of predation events we documented occurred during the nestling period. This may reflect less intensive video monitoring during the early incubation period in Saskatchewan, given that 94% of our sampling period occurred after the sixth day of incubation. On the other hand, our data may reflect real predation patterns. Assuming 13 days for incubation and 12 days for brood rearing (Davis 2009), 79% of video-monitored pipit nests survived the incubation period and 64% survived the nestling period. Incubation and nestling stage survival was 21% and 7%, respectively, for all 187 nests monitored in Saskatchewan (S. K. Davis, unpubl. data). Furthermore, past studies found pipit nest survival to be influenced by nest age, with nest survival being highest during the

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incubation period and lowest during the nestling period (Davis 2003, Jones and Dieni 2007, Jones et al. 2010), particularly just prior to fledging (Davis et al. 2006). Davis (1994) found a similar pattern for pipits and four other grassland songbird species in Manitoba. Patterson and Best (1996) reported higher survival rates during the incubation period for four of five species breeding in Iowa. The lower survival rates during the nestling period may be due to diurnal predators cueing on the increased activity of adults feeding young and nestlings begging for food (Haskell 1994). Indeed, Dohms (2009) found that provisioning rates of pipits increased as the young aged. Furthermore, video recording revealed increased nestling activity inside and outside the nest a few days prior to fledging (S. K. Davis, unpubl. data). Video recording also allowed us to document interesting behaviors of pipits and nest predators. We documented three cases of nest defense against thirteen-lined ground squirrel. In each case, the ground squirrel arrived when the pipit was away from the nest and the pipits attacked the squirrel upon arrival, with mixed results. In two cases the ground squirrel ran off with a single nestling, while in the third case the female pipit thwarted the ground squirrel from removing nestlings during the first attack only. The ground squirrel returned to the nest on two separate occasions and killed all the nestlings despite the attacks from the female. The male (color banded) was also observed at the nest, but we could not determine whether he assisted the female in the attacks. The frequency or success of nest defense by pipits is difficult to assess because of the limited field of view of the cameras and our review of videotapes in Saskatchewan was restricted to nests with known predation events (see also Pietz and Granfors 2005). However, nest defense by pipits appears to be a useful strategy against smaller predators, as two of the three nests successfully fledged young. This may in part explain why all but one nest predation by small mammals and western meadowlarks occurred while the adult pipits were away from the nest. In contrast to diurnal predation events, females were typically on the nest just prior to nocturnal predations and departed the nest shortly after the arrival of the predator. Over the years, we have often noticed partial egg and nestling loss while monitoring grassland bird nests. We suspected that predators were

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removing eggs and nestlings between our nest visits, but had no way of confirming our suspicions. Although we could not determine whether the same individual was responsible for multiple predation events, we did confirm that the same species was responsible for partial predation events on different days. Thirteen-lined ground squirrels were observed depredating nests on two consecutive days at one nest and three consecutive days at another nest. We also documented Western Meadowlarks preying upon the same nest on two consecutive days at two different nests. Future studies might consider determining whether individuals exposed to partial nest predation alter their nest attendance behavior in an attempt to thwart future predation attempts. Our only other case of multiple visits by the same nest predator involved a gartersnake. A gartersnake visited the nest during the incubation stage but did not consume any of the eggs. A gartersnake then visited the nest prior to fledging and captured at least one nestling. Some researchers question whether snakes might delay depredating nests containing eggs until the nestlings develop, to take advantage of the increased nutrient reward (L. A. Powell, pers. comm.). Not all multiple predation events were due to one species. We documented one case of predation first by a thirteenlined ground squirrel, followed by striped skunk two days later. We could not determine whether the two events were completely independent or whether partial predation by the ground squirrel provided visual or olfactory cues for the skunk. The diverse predator communities documented destroying grassland songbird nests present many challenges for land managers attempting to increase reproductive success of pipits and other grassland songbirds. The predator guilds documented in camera studies to date are associated with a variety of habitats, with some species associated with edge habitat (e.g., striped skunk) and others occupying interior grasslands (e.g., thirteen-lined ground squirrel) (Renfrew and Ribic 2003, Renfrew et al. 2005, Grant et al. 2006). However, further research on identification of nest predators provides an important step toward informed and effective management for grassland songbirds (Thompson and Ribic, chapter 2, this volume). Given the importance of Northern Harriers and thirteen-lined ground squirrels as predators of pipit nests in our studies, future research should examine the foraging ecology NO. 43

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and behavior of these species to gain an understanding of how local and landscape-level factors influence their abundance. In addition, experimental studies are needed to determine whether deer are more likely to depredate nests with cameras or nest markers, given the number of camera nests taken by these animals in Saskatchewan and North Dakota (Pietz and Granfors 2000b). ACKNOWLEDGMENTS The Saskatchewan project was funded by Environment Canada–Canadian Wildlife Service, Government of Canada Interdepartmental Recovery Fund for Species at Risk, National Science and Engineering Research Council of Canada (NSERC), and Saskatchewan Environment Fish and Wildlife Fund. We thank R. Fisher, T. Friesen, K. A. Martin, L. D. Parker, E. Perlett, D. J. Sawatzy, J. M. Szarkowicz and a number of volunteers for their invaluable assistance in the field. Thank you to K. Hecker and the staff at the Last Mountain Lake National Wildlife Area for their support and hospitality, and to C. Fendelet and the Agri-Environment Services Branch for access to their land. We are grateful to D. G. McMaster (Saskatchewan Watershed Authority), T. I. Wellicome (Canadian Wildlife Service), and R. G. Poulin (Royal Saskatchewan Museum) for the generous loan of video monitoring systems. The Montana project was funded by the U.S. Fish and Wildlife Service, Nongame Migratory Bird Program, Region 6. Field support and resources were provided by J. E. Cornely, C. R. Luna, D. M. Prellwitz, and the staff at Bowdoin National Wildlife Refuge. We thank the many dedicated field assistants who worked on this project over the years, particularly P. J. Gouse, who was instrumental in the work and completion of this project. Thanks to P. J. Pietz for the generous loan of video monitoring systems. Comments from D. A. Granfors, P. J. Pietz, L. A. Powell, and F. R. Thompson III greatly improved the manuscript. The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service or the Canadian Wildlife Service.

LITERATURE CITED Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2000. COSEWIC assessment and status report on the Sprague’s Pipit (Anthus spragueii) in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa, ON. Creighton, P. D., and D. K. Porter. 1974. Nest predation and interference by Western Meadowlarks. Auk 91:177–178.

Davis, S. K. 1994. Cowbird parasitism, predation, and host selection in fragmented grassland of southwestern Manitoba. M.S. thesis, University of Manitoba, Winnipeg, MB. Davis, S. K. 2003. Nesting ecology of mixed-grass prairie songbirds in southern Saskatchewan. Wilson Bulletin 115:119–130. Davis, S. K. 2009. Re-nesting intervals and duration of the incubation and nestling periods of Sprague’s Pipits. Journal of Field Ornithology 80:265–269. Davis, S. K., R. M. Brigham, T. L. Shaffer, and P. C. James. 2006. Mixed-grass prairie passerines exhibit weak and variable responses to patch size. Auk 123:807–821. Davis, S. K., and R. J. Fisher. 2009. Post-fledging movements of Sprague’s Pipit. Wilson Journal of Ornithology 121:198–202. Davis, S. K., and W. E. Lanyon. 2008. Western Meadowlark (Sturnella neglecta). Birds of North America No. 104, Academy of Natural Sciences, Philadelphia, PA. Davis, S. K., and S. G. Sealy. 2000. Cowbird parasitism and nest predation in fragmented grasslands of southwestern Manitoba. Pp. 220–228 in J. N. M. Smith, T. L. Cook, S. I. Rothstein, S. K. Robinson, and S. G. Sealy (editors), Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, TX. Davison, W. B., and E. Bollinger. 2000. Predation rates on real and artificial nests of grassland birds. Auk 117:147–153. Dohms, K. M. 2009. Sprague’s Pipit (Anthus spragueii) nestling provisioning and growth rates in native and planted grasslands. M.S. thesis, University of Regina, Regina, SK. Donald, T. G. 2009. Environmental and temporal influences on incubation attentiveness by Sprague’s Pipit (Anthus spragueii). Honours thesis, University of Regina, Regina, SK. Grant, T. A., E. M. Madden, T. L. Shaffer, P. J. Pietz, G. B. Berkey, and N. J. Kadrmas. 2006. Nest survival of Clay-colored and Vesper Sparrows in relation to woodland edge in mixed-grass prairies. Journal of Wildlife Management 70:691–701. Haskell, D. 1994. Experimental evidence that nestling behaviour incurs a cost to nest predation. Proceedings of the Royal Society of London, Series B: Biological Sciences 257:161–164. Hernandez, F., D. Rollins, and R. Cantu. 1997. An evaluation of Trailmaster® camera systems for identifying ground-nest predators. Wildlife Society Bulletin 25:848–853. Jones, S. L., and J. S. Dieni. 2007. The relationship between predation and nest concealment in mixed-grass prairie passerines: an analysis

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using program MARK. Studies in Avian Biology 34:117–123. Jones, S. L., J. S. Dieni, and P. J. Gouse. 2010. Reproductive biology of a grassland songbird community in northcentral Montana. Wilson Journal of Ornithology 122:455–464. Larivière, S. 1999. Reasons why predators cannot be inferred from nest remains. Condor 101:718–721. MacIvor, L. H., S. M. Melvin, and C. R. Griffin. 1990. Effects of research activity of Piping Plover nest predation. Journal of Wildlife Management 54:443–447. Major, R. E., and C. E. Kendal. 1996. The contribution of artificial nest experiments to understanding avian reproductive success: a review of methods and conclusions. Ibis 138:298–307. Martin, T. E. 1993. Nest predation among vegetation layers and habitat types: revising the dogmas. American Naturalist 141:897–913. Patterson, M. P., and L. B. Best. 1996. Bird abundance and nesting success in Iowa CRP fields: the importance of vegetation structure and composition. American Midland Naturalist 135:153–167. Phillips, M. L., W. R. Clark, M. A. Sovada, D. J. Horn, R. R. Koford, and R. J. Greenwood. 2003. Predator selection of prairie landscape features and its relation to duck nest success. Journal of Wildlife Management 67:104–114. Pietz, P. J., and D. A. Granfors. 1998. A miniature camera system for studies of grassland passerine nests. ⬍http://www.npwrc.usgs.gov/resource/birds/ nestcam/index.htm⬎ (16 March 2011). Pietz, P. J., and D. A. Granfors. 2000a. Identifying predators and fates of grassland passerine nests using miniature video cameras. Journal of Wildlife Management 64:71–87. Pietz, P. J., and D. A. Granfors. 2000b. White-tailed deer (Odocoileus viginianus) predation on grassland songbird nestlings. American Midland Naturalist 144:419–422. Pietz, P. J., and D. A. Granfors. 2005. Parental nest defense on videotape: more reality than “myth.” Auk 122:701–705. Renfrew, R. B., and C. A. Ribic. 2003. Grassland passerine nest predators near pasture edges identified on videotape. Auk 120:371–383.

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Renfrew, R. B., C. A. Ribic, and J. L. Nack. 2005. Edge avoidance by nesting grassland birds: a futile strategy in a fragmented landscape. Auk 122:618–636. Robbins, M. B., and B. C. Dale. 1999. Sprague’s Pipit (Anthus spragueii). Birds of North America No. 439, Academy of Natural Sciences, Philadelphia, PA. Sanders, M. D., and R. F. Maloney. 2002. Causes of mortality at nests of ground-nesting birds in the Upper Waiteaki Basin, South Island, New Zealand: a 5-year video study. Biological Conservation 106:225–236. Sargeant, A. B., R. J. Greenwood, M. A. Sovada, and T. L. Shaffer. 1993. Distribution and abundance of predators that affect duck production: prairie pothole region. Resource Publication No. 194. U.S. Department of Interior, Fish and Wildlife Service, Washington, DC. Sauer, J. R., J. E. Hines, and J. Fallon. 2008. The North American Breeding Bird Survey, results and analysis 1966–2007. ⬍http://www.mbr-pwrc.usgs.gov/ bbs/bbs.html⬎ (16 March 2011). Schaeff, C., and J. Picman. 1988. Destruction of eggs by Western Meadowlarks. Condor 90:935–937. Shaffer, T. L. 2004. A unified approach to analyzing nest success. Auk 121:526–540. Thompson, F. R., III, and D. E. Burhans. 2004. Differences in predators of artificial and real songbird nests: evidence of bias in artificial nest studies. Conservation Biology 18:373–380. U.S. Fish and Wildlife Service (USFWS). 2010. Endangered and threatened wildlife and plants: 12-month finding on a petition to list Sprague’s Pipit as endangered or threatened throughout its range. ⬍http:// www.fws.gov/mountain-prairie/species/birds/ spraguespipit/75FR56028.pdf⬎ (10 May 2011). Williams, G. E., and P. B. Wood. 2002. Are traditional methods of determining nest predators and nest fates reliable? An experiment with Wood Thrushes (Hylocichla mustelina) using miniature video cameras. Auk 119:1126–1132. Winter, M. 1999. Nesting biology of Dickcissels and Henslow’s Sparrows in southwestern Missouri prairie fragments. Wilson Bulletin 111:515–527.

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PART FOUR

Technology

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CHAPTER FIFTEEN

Development of Camera Technology for Monitoring Nests W. Andrew Cox, M. Shane Pruett, Thomas J. Benson, Scott J. Chiavacci, and Frank R. Thompson III

Abstract. Photo and video technology has become increasingly useful in the study of avian nesting ecology. However, researchers interested in using camera systems are often faced with insufficient information on the types and relative advantages of available technologies. We reviewed the literature for studies of nests that used cameras and summarized them based on study objective and the type of technology used. We also designed and tested two video systems that we used for three nest predator and behavioral studies. We found 327 studies that recorded 255 bird species spanning 19 orders. Cameras were most commonly used to study nest predators (n ⫽ 114), feeding ecology (n ⫽ 103), and adult behavior (n ⫽ 81). Most systems (69%) were partially or completely user-built. Systems that recorded in real time (ⱖ25 frames per second), time-lapse (⬍25 fps), and still images were all common, though their use tended to vary by study objective. Using the

time-lapse digital video recording systems we designed, we monitored 184 nests of 15 different species. We generally found these low-cost systems (US$350–725 per unit) to be reliable. Sources of data loss were variable by study but included digital recorder malfunction, power failure, and video cable damage due to rodents. Our review of the literature and our own experiences suggest that researchers carefully consider their objectives and study systems when choosing camera technology. To facilitate selection of the appropriate system, we describe general video system design and offer recommendations for researchers based on commercially available system components.

n 1956, Gysel and Davis presented an “automatic photographic unit for wildlife research,” which they baited with dove eggs to identify potential predators. Three years later, Royama (1959) published the specifications for an “auto-

cinematic food-recorder” which automatically triggered photographs of prey in the bills of Great Tits (Parus major) each time they perched on a trigger mechanism at the entrance of their nest-box. In the subsequent 50 years, ornithologists have employed

I

Key Words: behavior, camera, digital video recorder, nest monitoring, parental care, photography, predation, time-lapse, video.

Cox, W. A., M. S. Pruett, T. J. Benson, S. J. Chiavacci, and F. R. Thompson III, 2012. Development of camera technology for monitoring nests. Pp. 185–210 in C. A. Ribic, F. R. Thompson III, and P. J. Pietz (editors). Video surveillance of nesting birds. Studies in Avian Biology (no. 43), University of California Press, Berkeley, CA.

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photo and video technology to study birds at their nests with increasing frequency. Such technology allows for the collection of data that would otherwise be impractical to obtain because of logistical and/or financial constraints. Common research questions that can be addressed with cameras include nest predator identification (Hussell 1974, Thompson et al. 1999, Pietz and Granfors 2000), parental care (Grundel 1987, Cartar and Montgomerie 1987), prey identification (Hanula and Franzreb 1995, Grønnesby and Nygård 2000), and nestling behavior (McRae et al. 1993, Nathan et al. 2001). Cameras also provide researchers with glimpses of extremely rare events or unknown behaviors [egg and nestling cannibalism (Gilbert et al. 2005, Ben-Dov et al. 2006); helping at nests of non-cooperatively breeding species (Guzy et al. 2002)] that would otherwise go undetected. Despite the obvious value and increasingly common use of camera technology, ornithologists are often faced with more questions than answers when it comes to deciding on the type of equipment to use. Furthermore, reliable implementation of wildlife surveillance equipment is sometimes easier said than done; adverse field conditions or a lack of technical expertise can seriously hinder data collection. There have been two previous literature reviews that offered guidance on the video surveillance of nests. Cutler and Swann (1999) provided a useful guide to equipment based on study objectives, though it is now more than a decade old and provides little practical technical help given the rapid pace of innovation. Reif and Tornberg (2006) filled this gap in their more recent review, which focuses on use of digital video systems. Both papers should be read by any researcher interested in using cameras at avian nests. Our objectives were to (1) provide an updated review of camera studies focusing on the technology used to address common research questions, (2) report on user-built systems we used to monitor nests, and (3) provide recommendations on technical aspects of video systems for nest surveillance.

METHODS Literature Review In January 2009 we used Biblioline Wildlife and Ecology Studies Worldwide and Scopus to find original, peer-reviewed research which used

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camera technology to monitor avian nests. We used the keyword nest with keywords photo, video, or camera. We read all bird-related papers from the resulting output and used their cited literature to find other papers not captured by our search criteria. This approach did not provide a comprehensive list of studies that used video technology because these databases only index titles, keywords, and abstracts, whereas in many cases the use of video technology is first mentioned when methods are presented. Nevertheless, our approach provided us with an ample number of papers for this review. We noted whether the study used analog (i.e., VCR) or digital recording units; the method of recording [e.g., still photos, real-time (ⱖ25 frames per sec) or time-lapse (⬍25 frames per sec) video, 24-hr (continuous) or subsampled hours, with or without triggering mechanism]; and the source of equipment [i.e., vendor-built (professionally designed and constructed) or user-built (at least partially designed and constructed by the researcher)]. We assumed that papers using camera systems more complex than a simple hand-held recorder would provide vendor information when applicable. We also recorded whether the camera system was used with artificial or real nests, and in the latter case we recorded the focal species studied. Finally, we recorded the stated objective(s) for each study. In many papers we could not adequately determine some of the information we were seeking, so sample sizes for summary statistics presented below are variable. Case Studies In 2007–2009 we designed and tested two userbuilt digital video monitoring systems (referred to as System One and System Two when necessary hereafter; see Table 15.1 for a detailed list of components). Both systems consisted of a miniature digital video recorder (DVR), a battery, and a BNC power/video extension cable (10–30 m) that connected the recorder to a weatherproof, day/night security camera (Fig. 15.1). System One included a voltage converter because the DVR and camera operated at different voltages. We housed the recorder, voltage converter, and battery in either a waterproof Pelican™ 1500 case or a camouflaged 18–30 gallon plastic container. We used six different fixed-focus camera models that ranged from $30 to $170 (USD). All NO. 43

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TABLE 15.1 List of major components and their costs (USD) for two user-built digital video systems designed for nest predator identification studies.

Component

System One

Cost

System Two

Cost

DVR

Yoko Tech RYK9122

$190

Seorim AKR-100

$150

Camera

Rainbow CCTV BB22WIRC*

$160

Supercircuits PC6EX-3* Supercircuits PC6EX-4 Supercircuits PC331-IR Supercircuits PC506-IR Supercircuits PC168-IR

$30 $50 $70 $90 $90

Voltage converter

ESCO-Ohio 3-terminal

$20

Waterproof case

Pelican™ 1500

$70

plastic containers

$3, $10

Video/power cable

15 m BNC

$20

30 m BNC

$25

Battery

Sealed lead-acid Werker WKA112-26NB

$85

deep-cycle (various)

$60–80

Battery charger

Schumaker SC-600A

$40

various

$25–60

Memory cards

Various (4GB)

$10

various (8GB)

$20

Portable monitor

Supercircuits MON-1

$100

various

$80–435

NOTES: Camera models recorded color images except those marked with an asterisk (*), which recorded monochrome images.

portable monitor

camera

DVR battery

power/video cable

voltage converter

Figure 15.1. Schematic of a user-built digital video recording (DVR) system. The dashed line surrounds components housed in a waterproof case. Components in gray boxes may not be required; some DVR models have integrated liquid crystal displays and some may operate at the same voltage as the camera (typically 12 volts).

but the two least expensive models were weatherproof; we sealed the latter models with a plastic coating and housed them within a PVC cap to prevent moisture penetration. For nighttime illumination, the most expensive model was equipped with infrared (IR) light-emitting diodes (LEDs) that emitted light at a peak wavelength of 940 nm; the rest had LEDs with a peak wavelength of 850 nm. We had the vendor replace the wide-angle 3.6-mm lens with a 12-mm lens on the most expensive model, which allowed for camera placement at greater distances from nests. The lenses on the remaining five models ranged from 3.6 to 8 mm. We used paint, natural vegetation, and/or tree bark to improve camera concealment. We used two different DVR models. The DVR for System One allowed for three resolution settings up to 704 ⫻ 480 (vertical ⫻ horizontal lines), while System Two’s DVR only recorded at a low resolution (352 ⫻ 240). Image compression rate options (i.e., the amount of detail stored per frame) provided three different recording qualities, and the number of frames recorded per second (fps) ranged from 1 to 30. Time and date stamps could also be added to the video. Images were stored on 4–8-GB SD or SDHC memory cards (not supplied with the DVR). The typical duration of a recording period was 2–4 d and was dependent upon the settings we chose (usually 6 fps of normal or high-quality video at the lowest resolution) and the memory card capacity. However, both DVRs used a memory-saving algorithm which resulted in differing memory requirements for each nest (i.e., the number of hours of video that could be recorded differed based on camera field of view, amount of movement within the field of view, etc.), so we would adjust settings in the field as needed. Both DVRs also had a motion-detection feature that could save substantial storage space (see discussion), but we did not test this option. We powered each unit with a single deep-cycle marine battery (75–125 amp hr) or a sealed leadacid battery (26 amp hr). The total cost per system, including SD cards, batteries, chargers, and a small digital monitor for confirming system function and checking camera alignment ranged from $350 to $725 per unit when multiple units are purchased (if cameras are tended to on alternating days, two units can share a battery charger, replacement batteries, and SD cards).

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We tested our video systems in 2007–2009 at field sites in Missouri, Illinois, and Arkansas. In Missouri and Illinois, we deployed cameras at passerine nests in shrublands and forests. We typically placed cameras 1–4 m from nests, mounted on a tripod or wooden dowel, attached to thin (~1–4 cm) branches with a spring-loaded metal clip, or affixed to a tree trunk with brown duct tape or with a custom-made cargo strap. In Arkansas, we deployed cameras at Mississippi Kite (Ictinia mississippiensis) nests. Because these nests may be located ⬎30 m above the ground, we sometimes joined multiple 30-m BNC cables using female–female BNC couplers prior to climbing to the nest. The camera was attached to the limb of the nest tree, 0.4–0.5 m above the nest, using camouflaged plastic cable ties. For all mounting methods, we sprayed the extension cable and exposed camera wires with Ropel®, a nontoxic chemical, to deter wildlife from damaging them. We camouflaged all components of the system with small branches, leaves, and other vegetation to prevent predators from being affected by the equipment (Herranz et al. 2002, Richardson et al. 2009) and to maximize the likelihood of nesting birds accepting the camera. We placed the waterproof case 8–10 m from passerine nests and approximately 30 m from raptor nests to minimize disturbance to the nesting bird when changing the battery and memory card. The total time for camera setup was generally ⬍15 min for one person at passerine nests and ~1 hr for two people at raptor nests. Once out of the field, we downloaded data from the SD cards to an external hard drive using a standard SD card reader. The more expensive DVR broke the total time recorded into separate 1-MB files. This resulted in thousands of files for a 48-hr recording period, but it also allowed for easy manipulation of files (e.g., sections of video were easily deleted or stored in separate places). The files were in MPEG-4 format, which is compatible with many freely available media players, but we chose to use Windows Media Player 11 because it allows multiple files to be queued for sequential play. The other DVR stored files in 30-min increments in a proprietary format that required special software to view, but those files could also be converted to a commonly used file format for viewing on most players.

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RESULTS Literature Review We found 327 journal articles that mentioned use of photo or video technology (Table 15.2), the frequency of which increased over time (Fig. 15.2; see Appendix 15.1 for a complete list of articles). Three primary types of recording equipment were used. Systems that record in real time (ⱖ25 fps) were used regularly (27% of all publications), but most of these did not continuously record data at nests 24 hr per day (e.g., many recorded 2- or 4-hr samples). Time-lapse video systems, which record at ⬍25 fps, were most common (38%). Systems with manual or IR triggers that took still photos of nests were also common (33%). Less commonly used were video systems that did not record images (8%; usually associated with checking nest contents). Digital technology was used in 11% of studies since its first use in 2003 and in 21% of studies since 2006. Twenty percent of these systems were built by vendors and 11% were unmodified handheld video cameras. The remaining 69% of systems required some assembly by the end user. The user-built video systems varied greatly in

sophistication and purpose. Nest-checking equipment included cameras designed to allow access to nests of canopy, cavity, or burrow-nesting species that would otherwise be unreachable (e.g., Dyer and Hill 1991, Proudfoot 1996). Systems for monitoring adult behavior were often simple modifications of hand-held camcorders (e.g., Honza and Moskát 2008) but also included some impressive uses of wireless (King et al. 2001), solar (e.g., Margalida et al. 2006), and satellite (e.g., Momose et al. 2003) technologies. The studies using camera technology recorded data for 255 species from 19 orders. We identified eight broad categories that encompassed most papers’ study objectives (Table 15.2). Cameras were most commonly used to identify nest predators, but they also were frequently used in studies of adult and nestling behavior, especially related to feeding ecology. Many papers presented user-built video systems, including systems used to identify the contents of otherwise inaccessible nests. Studies reporting extra-pair adults (conspecific and otherwise) that visited the nest were less common. Finally, a small number of studies evaluated the impact or efficacy of video cameras or other technology (e.g., radio transmitters) at avian nests.

TABLE 15.2 Number of studies published during 1956–January 2009 that used camera technology (see Appendix 15.1), listed by study objective and type of recording technology used.

% of studies in category Study category

No. studies

Still

Time-lapse

Nest predator identification

114

50

43

6

Feeding ecology

103

28

32

40

Adult behavior

81

6

45

43

Present a user-built system

32

39

35

26

Nest contents identification

23

Nestling behavior

19

0

21

79

Camera or technique evaluation

15

25

58

17

Intruder behavior

13

0

45

55

7

0

60

40

Other

Real-time

NOTES: Studies that had multiple objectives are included in more than one category. When calculating percentages, we excluded systems that were not adequately described or did not have a recording unit. Mechanical or infrared triggers were used in all but one still-frame system, which used digiscoped photos. Triggers were used in 4% of time-lapse systems and 12% of systems that provided real-time (ⱖ25 fps) video. Feeding ecology studies include studies on provisioning rates, food loads, and prey identification. Adult behavior studies include studies on nest defense by parent birds and helpers in cooperatively breeding species and on breeding behavior other than feeding (e.g., nest attentiveness). With one exception (Hudson and Bird 2006), systems used to check nest contents relayed images to a video screen but did not record them. Intruder behavior studies include studies on brood parasites and conspecific adults of non-cooperatively breeding species.

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35

Number of publications

30 25 20 15 10 5 0 1960

1970

1980 Year

1990

2000

Figure 15.2. Camera technology has been used with increasing frequency between 1956 and 2007, the last year in which papers were fully indexed when we performed our literature search.

Case Studies We obtained video footage at 125 nests of ten species and determined the cause of failure at 53 of 66 unsuccessful nests with System One. At one nest, the female disappeared 9 d after camera setup, but the extended period between camera installation and the female’s disappearance suggests the abandonment was not caused by our activities. At two nests we were not able to identify a predator even though the camera was functioning correctly. We removed cameras at four nests prior to nest failure, and we failed to record predation events at seven nests because of technician error (n ⫽ 3), video system malfunction (n ⫽ 3), or because a camera fell (n ⫽ 1). In all other cases, predators were identified to guild (e.g., raptor, mouse, snake). Although many images were clear (Fig. 15.3A), poor video quality associated with the distance between the nest and the camera (i.e., cameras too close to nests were out of focus and those that were too far had insufficient detail to identify small predators) prevented species identification of 16 of 50 (31%) of the recorded predators (Fig. 15.3B). In 2009, we tested a color camera with manual focus and zoom controls to alleviate this problem, but image quality was generally worse (Fig. 15.3C). Predators not identified to species included all rodents (n ⫽ 7), five of 22 raptors, and four of seven snakes.

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We obtained video footage at 53 nests of nine passerine species using System Two and determined the cause of failure at 27 of 29 failed nests. Image quality was generally quite good (Fig. 15.3D) and we were able to identify all predators except for one mammal to species. In Arkansas, we collected video data from six Mississippi Kite nests. We recorded one predation event by a Texas ratsnake (Pantherophis obsoletus; formerly black ratsnake, Elaphe obsoleta) and documented a non– predator-related failure caused by a severe thunderstorm that degraded the nest, causing the egg to fall through it while the adult was incubating. System One’s reliability was lower than expected in 2007. We failed to record data on 121.5 of 758 d (16% failure rate). Of all causes of system failure, the most frequent were a DVR firmware malfunction that prevented the download of files (64% of failure days) and faulty wiring between the battery and the recorder (10%). We installed a firmware upgrade from the DVR manufacturer prior to the 2008 season and the reliability of our systems improved; we failed to record data on 51 of 928 d (6% failure rate). However, our voltage converters did not function as expected and several DVRs began to perform erratically or fail completely (30% of all failure days). The second video system generally performed reliably; we only failed to record data on 32 of 743 d in the field (4% failure rate) and did not have any notable NO. 43

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A

B

C

D

Figure 15.3. Sample images from our case studies. (A) a Broad-winged Hawk (Buteo platypterus) depredates an Acadian Flycatcher nest. The same fixed-focus camera provided lower-quality images when placed closer to a nest (B). The video was out of focus in the day and worse at night; the Indigo Bunting (B, top arrow) is barely visible, and the mouse (bottom arrow) cannot be identified to species. Some camera models rarely provided good images; the camera that recorded the image of a hawk (C, top arrow) depredating an Acadian Flycatcher nest (bottom arrow) usually produced pixelated images with poor contrast despite the fact that it had manual focus and zoom controls. In contrast, the fixed-focus model used to record the Texas ratsnake (D) typically provided high-quality color images.

technical problems. Causes of failure common to both systems include: exceeding the capacity of memory cards prior to the end of the recording period (8% of combined failure days for both systems), power failure when batteries died prematurely (7%), and rodents chewing through wiring (6%).

DISCUSSION Video systems are being used with increasing frequency because they facilitate efficient collection of data on many aspects of avian reproductive biology that would otherwise be impractical or impossible to obtain. Their use across a broad array of avian taxa and study objectives demonstrates their wide range of utility but also indicates that there is no single ideal system. As such, it can be difficult to determine what kind of system is optimal for a particular study. Our

literature review and experience in the field suggest that careful consideration of one’s study objectives combined with an understanding of the components of commonly used video systems are needed to choose the right system. Although we cannot offer advice related to study objectives, we believe the following guide can help researchers understand the basic technology involved in most video systems used to monitor bird nests. Image-recording Units Camcorders, Trail Cameras, and Still-frame Cameras The first question researchers should ask is whether off-the-shelf equipment will suffice to meet their study objectives. These are often the least expensive, least time-consuming options (hand-held camcorders, trail cameras, still-frame

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cameras) and do not require separate camera and recording components. Clearly, commercially available video cameras that record in real time for relatively short durations are not desirable for nest predation studies, but their relatively low cost (many models are available for ⬍$300) and ease of use make them well suited for behavioral studies where subsampled time periods are standardized among nests (e.g., food-provisioning or incubation behavior). These cameras, however, are generally not designed for prolonged outdoor use, and measures should be taken to safeguard equipment from adverse field conditions. Still-frame cameras have been used primarily for nest predator identification and feeding ecology studies (the latter almost exclusively with cavity-nesting species). For both study objectives, researchers have typically used systems that only record images when a mechanical or IR trigger is tripped (reviewed in Reif and Tornberg 2006). Mechanical triggers coupled with still-frame cameras are now used primarily in conjunction with artificial nests to identify nest predators (79% of studies from 1990 to 2007), but such use may not be warranted. In addition to the biases associated with artificial nests (Buler and Hamilton 2000, Thompson and Burhans 2004), camera shutter sounds can disrupt predation events and single images (many still-frame models cannot take rapid successive photos) may not provide conclusive evidence of a predation event (Pietz and Granfors 2000). Further, even when used at real nests, still-frame cameras and mechanical triggers may systematically undersample certain predator guilds during the nestling stage (Liebezeit and George 2003). IR triggers can be active (a transmitter emits an IR beam to a receiver placed on the opposite side of the nest) or passive (a receiver detects changes in radiant IR levels). Active triggers take longer to set up and may not perform as well as passive ones (Bolton et al. 2007), but researchers have experienced problems with passive triggers as well (Hernandez et al. 1997). For example, passive triggers may be activated by abiotic factors such as temperature and/or sunlight changes, and they may not be sensitive to the movement of small animals (Brown and Gehrt 2009). Both passive and active IR triggers used with either camcorders or still-frame cameras are external to the recording device, which results in a pause (typically ⱕ0.5 sec) between motion detection and camera activation.

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The newest triggers can have very short pauses (ⱕ0.15 sec) that minimize the risk of lost data. Nevertheless, in some study systems certain events [nest predation by ants (Stake and Cimprich 2003, Connor et al. 2010) or harvestmen (Benson et al. 2010)] may not activate triggers, while in other cases they may be frequently activated by non-targeted events such as moving vegetation. Trail cameras, such as those used by hunters to identify game animals, usually integrate passive IR triggers and cameras (typically still-frame, but newer models offer video as well) into a single unit and are explicitly designed for extended deployment in the field. They are more energy efficient than systems that record continuously, so most models run off household batteries. Many models are larger than cameras used in other nest monitoring systems and are usually equipped with wide-angle lenses; these factors make them impractical for some species, but they may be cost effective, off-the-shelf tools for recording images at nests of larger species (Dreilbelbis et al. 2008). The newest, most expensive models are more compact and have been used at passerine nests, but even those placed within 1 m of the nest did not capture all predation events because the IR trigger sometimes failed to detect movement at the nest (G. Londoño, pers. comm.).

Digital Recorders While systems that record continuously for extended durations may be too expensive and unneeded for many study objectives, they are usually necessary for identifying nest predators. Rapid advances in digital technology have resulted in the production of sophisticated DVRs and highcapacity flash memory, which allow for the capture and storage of high-quality digital video. These devices can be integrated by vendors or end users into video monitoring systems like those used in our case studies. Digital equipment is lighter, more reliable, less expensive, and uses less power than comparable analog components that were commonly used in the past; we see little reason for researchers to consider analog equipment. There is a variety of DVRs available in the marketplace suitable for monitoring bird nests. The models we used in our case studies were small (both DVRs we used were ⱕ6 ⫻ 9 ⫻ 2 cm) and offered a number of options (e.g., resolution, frame rate, video quality) often found in other NO. 43

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models as well. One feature we did not test was the integrated passive triggers (i.e., motion detection recording options) that eliminate the pause between the trigger and camera activation previously described by including 0.5 sec of video prior to activation of the trigger. This kind of trigger was tested by Bolton et al. (2007), was successfully used in several subsequent studies (Morris and Gilroy 2008, Stevens 2008), and can drastically reduce memory usage. Regardless, we chose not to use the motion detection options of our DVRs because of concerns about the detectability of some predators. Several options our DVRs lacked may be useful to other researchers. First, many portable DVRs have integrated hard disk drives, which offer greater storage capacity than the SD cards we used with our DVRs. These DVRs can significantly extend deployment periods or allow researchers to gather higher-quality video (i.e., increased resolution or frame rate). However, downloading the data from the DVR in the field can be time consuming and may require a laptop or extra DVRs to replace those with full hard drives (Pierce and Pobprasert 2007). Second, our DVRs required a small portable monitor to view the recording settings, but other models have integrated liquid crystal displays (LCDs), which eliminate the need for an external monitor. Portable monitors are relatively inexpensive and have other uses as well (see below), so integrated LCDs may not be worth the extra cost for some researchers. Finally, for study systems with high nest densities, multi-channel DVRs allow researchers to simultaneously record video from multiple nests (Colombelli-Négrel et al. 2009). Cameras for Use with DVRs Many types of cameras can be effectively deployed at nests, but the most useful types are likely those designed for security applications. A major advantage of these cameras is that many are designed for outdoor use and are therefore able to withstand extreme temperatures and precipitation, and most are designed to use a 12-V DC power source. Depending on the features included, these cameras vary greatly in size and in the power they consume. Price also tends to vary with the features included, but many field-worthy cameras are available for ⬍$150. Cameras offer different levels of resolution (described by the

number of horizontal lines that compose a frame, also called TVL), but researchers will only benefit from increased camera resolution if they are also recording in high resolution. For example, if a DVR is recording at low resolution (352 ⫻ 240), then images from all cameras with ⱖ240 TVL will have the same resolution when played back. Cameras come with or without IR LEDs for night recording; models that provide nighttime illumination have variable effective ranges depending upon the type and number of LEDs. Some substrates absorb rather than reflect IR light, which can result in an effective range that is smaller than that specified by the camera manufacturer (Sabine et al. 2005). Separate IR illuminators can also be used to provide additional light for night recording, but these can only be used with cameras that have lenses sensitive to infrared light. An important consideration when choosing an IR illuminator or camera is the wavelength of light emitted by its LEDs. LEDs with shorter (850 nm) versus longer (940 nm) peak wavelengths tend to provide better lighting in near to total darkness and are much more commonly available, but they emit some light in the visible spectrum, which appears to humans as a faint red glow; LEDs with longer peak wavelengths emit light that is invisible to humans. The glow is only visible from a relatively narrow range of viewing angles and does not seem to affect predation rates (Sanders and Maloney 2002, this study’s AR and IL data), but to our knowledge no studies have explicitly investigated its influence on predator behavior. The focal length of camera lenses should also be taken into account when choosing a camera. Those with wide-angle lenses have shorter focal lengths, requiring them to be relatively closer to nests, but because cameras with wide-angle lenses remain focused at variable distances, the distance from camera to nest does not need to be exact to preserve picture quality. Lenses with longer focal lengths, on the other hand, can be situated farther from nests because they provide greater magnification, but they need to be placed at a more precise distance from the nest to avoid reduced picture quality. Our experience suggests that cameras with relatively wide-angle lenses (ⱕ8 mm focal length) work well when cameras can be placed close (e.g., ⱕ2 m) to nests. We used a camera with a longer focal length (12 mm) to film Acadian Flycatchers because their nest placement

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generally did not allow for cameras to be closer than 3 m. We recently disassembled two different fixed-focus camera models and found that adjusting the focal point of the lens can be done rapidly and easily, so we plan to do this during setup at nests in future years. However, we must caution that IR LEDs are matched with lenses to provide optimal lighting at specific distances, so adjusting or replacing lenses may reduce nighttime image quality. Many newer models offer variable zoom and focus options which can improve the flexibility of camera setup and placement without such a sacrifice, as the LEDs are configured to match the variable focal distances of the camera. However, even though the 940-nm camera we tested in 2009 had a 9–22-mm zoom color lens and manual focus controls, it did not operate well during the day in low light and image quality was very poor in heavily shaded habitats or at dusk and dawn. Color cameras will be necessary for researchers recording marked birds, and many of our color models performed quite well. But color images require more memory than black-and-white images, and our experience suggests that with some models colors can appear dull or washed out even when lighting is good, which limits their use for identifying color-banded birds. Our conversations with vendors suggest that in general, black-and-white cameras tend to produce sharper, less pixelated images, especially in cameras equipped with 940-nm LEDs. Recent advances in IR LEDs should result in cameras that provide brighter images at greater distances more efficiently than current models, and new lenses are being developed that provide increased clarity in IR-illuminated images. Other new technologies that may improve cameras for avian nest studies include digital noise reduction (DNR) and wide-dynamic-range (WDR) cameras, both of which are intended to improve image quality and reduce pixelation in low light conditions. Furthermore, new cameras are commercially available that amplify ambient light and do not require IR LEDs when recording at night, although we have not tested these. Regardless of the model chosen, we recommend that researchers test it under normal field conditions prior to purchasing in quantity or relying on it for highquality data collection. Security cameras are not designed specifically for wildlife studies, and not all models will perform as desired. For example, some of our cameras did not function well unless

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placed near enough to a nest for it to occupy a substantial portion of the field of view, which was not always possible. Furthermore, some species are much more sensitive than others to the presence of cameras and may require special models; adults at three Kentucky Warbler (Oporornis formosus) nests would not accept camouflaged cameras even when placed 4–5 m from the nest (W. Cox, pers. obs.). Other Technical Considerations Most of the video systems we found in the literature were powered by traditional lead-acid batteries. Deep-cycle marine batteries are cost effective and typically have high charge capacities but are relatively heavy (23–30 kg); sealed lead-acid batteries can be significantly lighter and are safer (there is little danger of acid burns) but are also more expensive. Lithium batteries are much more expensive than their lead-acid counterparts but are an effective way to drastically reduce the size and weight of a video system. Batteries have variable life spans, but many can be used for five field seasons or more. To maximize life span, batteries of all types should be charged at a low amperage (e.g., 2–6 amps) and should be charged periodically when not in use for extended periods. Solar panels have been used frequently over the past decade, and when combined with wireless transmitting technology they offer an ideal solution for researchers working in remote areas or with species whose nests are difficult to access (Margalida et al. 2006). Fuel cells are another expensive but useful power option for researchers lacking frequent access to nests and/or a power grid (www. sandpipertech.com/remote_power.html). Cables and connectors are also required in most systems to provide power to the components and transmit the video data to the recorder. The distance between the camera and its associated recording equipment and power supply should be great enough to allow researchers to download data and exchange batteries without flushing adult birds from the nest or inciting alarm calls from adults attending nestlings. Cables can be purchased in varying lengths or connected in series to allow the recording equipment to be placed far from the nest without noticeable signal degradation. Although separate power and video cables can be purchased, cables that combine both functions are commercially NO. 43

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available, generally sturdy enough for field use, and relatively inexpensive. In addition to these cables, connectors that convert between RCA and BNC plug types are generally needed, and short connectors with alligator clips that facilitate attachment to the battery are also useful; these are available from several sources including stores that sell electronics components. To prevent damage to the video/power cable, primarily by gnawing mammals, chemical deterrents are available (Ropel®) but do not always work. Other researchers have wrapped cables in aluminum tape (Booms and Fuller 2003) or buried them (Coates et al. 2008) to reduce the risk of damage. In areas where rodent damage was severe, we handled our cables with rubber gloves to reduce scent and mineral deposition and we concealed metal connectors with electric tape to prevent their theft by wood rats (Neotoma spp.). However, even with these deterrents occasional cable damage is likely inevitable, and researchers should purchase spare cables to prepare for this possibility. Some researchers (Pechacek 2005, King and DeGraaf 2006) have used wireless technology instead of cables to connect a camera to a DVR (reviewed in Reif and Tornberg 2006). This eliminates the risk of cable damage from rodents and allows for the study of nests that are difficult to access (Margalida et al. 2006), though a separate power source for the camera and transmitter is required and systems may require line-of-sight between transmitting and receiving antennas. A portable LCD viewing monitor is necessary for some DVRs and can be helpful during setup and nest checks for most systems. Monitors can be connected directly to a camera, which allows for efficient and exact camera placement. For DVR models without video screens, monitors are required to ensure proper camera placement, to view DVR menu options when changing recording settings (e.g., fps, resolution, picture quality), and to check the remaining memory on cards. Finally, some recent video systems have integrated computers which help researchers control and store data. Colombelli-Négrel et al. (2009) designed a system that used a computer to manage data from multiple video and audio recorders, while Grivas et al. (2009) constructed a wireless video/audio monitoring system that had a local computer receive, record, and transmit data to a remote computer (145 km from the nest) from which researchers could control the system.

User- Versus Vendor-built Systems For those who require a system more specialized than what is available off the shelf, an important consideration is whether to build their own or purchase one from a vendor. The majority of video systems used in the reviewed papers were at least partially user-built. Relative to vendor-built systems, a primary advantage of user-built systems is lower cost. For example, our systems cost approximately $350–725 per unit, which is significantly less than comparable vendor-built units (System One cost 苲33% of a comparable vendorbuilt unit at the time it was constructed in 2007). Repair costs are typically less expensive as well, as no labor charges or markups on components occur. Other researchers presenting user-built systems noted similar savings (King et al. 2001, Hudson and Bird 2006). These savings are especially pertinent for researchers using cameras to identify nest predators because sample sizes are often small and constrained by the number of cameras available. A user-built video system may not be the best choice for all biologists. Considerable time and effort went into manufacturing each system, and our initial experiences with System One were not wholly positive. We were unable to address image-quality issues associated with our fixedfocus cameras because we did not have the expertise to build a camera that fit our exact specifications and none were available commercially (most IR cameras have a peak wavelength of 850 nm). Furthermore, the reliability problems associated with our DVR and voltage converter were not easily diagnosed and resulted in the loss of data. Finally, our system lacks reverse polarity protection, so operator error can result in catastrophic failure of some system components. By contrast, vendor-built systems may offer greater reliability and more flexibility in system design, and do not require the user to diagnose and repair malfunctioning equipment. We cannot make an unambiguous recommendation as to whether researchers should use vendor- or user-built video systems. Vendor-built systems are often relatively expensive, and repairing them may not be possible in the field. But they can also offer researchers greater ease, reliability, and technical sophistication. User-built systems are much cheaper but require more knowledge, time, and effort to build. For researchers who

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do wish to explore building their own systems, we first recommend that they consult the literature (including this study) to learn what, if any, systems have been designed and used for their species and/or study objective. There are many good examples of video systems in the literature that can provide excellent guidance on general system design despite the fact that the rapid pace of technological developments makes many past systems functionally obsolete. We also think that researchers who custom-build a video system may benefit by consulting someone with electronics experience who can help identify potential pitfalls in design and component selection. In 2009, for example, we purchased inexpensive, professionally constructed voltage converters (ESCO-Ohio. com) to replace the problematic ones in our first case study; this fully resolved our problems with DVR failure (W. Cox, unpubl. data). Final Thoughts Miniaturized cameras coupled with digital recording and data storage are changing how we approach the study of avian reproductive ecology. The amount and quality of data that can be collected in a season with even a few well-placed cameras far exceeds what was previously possible with systematic or opportunistic observation by human observers. Furthermore, for some study objectives, cameras have demonstrated that older methods of data collection were either unreliable (Thompson and Burhans 2003) or heavily biased (Thompson and Burhans 2004). Video is not a bias-free panacea; nests monitored with cameras may have lower predation rates than those without cameras (Richardson et al. 2009) and care must be taken to minimize any effects on nesting birds or their predators. Regardless, video systems offer the promise of large volumes of high-quality data and are increasingly being used by ecologists to document and quantify events and behaviors that are difficult or impossible to observe directly. The study species and objectives will largely dictate specific needs, but the availability of funds for purchasing and maintaining multiple systems is a constraint for most studies. Once a system has been chosen, field tests are critical for assessing functionality, identifying potential problems, and developing protocols to troubleshoot those problems (e.g., availability of extra parts or on-site expertise).

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The use of stationary cameras to monitor nests is a well-established practice, but we are now reaching a degree of technological sophistication that will no longer restrict researchers to a stationary observation site. Perhaps the most exciting recent use of video is that of Rutz et al. (2007), who attached miniature cameras to New Caledonian Crows (Corvus moneduloides) to collect data on foraging behavior and tool use. These tiny cameras were combined with VHF radio transmitters, allowing the researchers to couple finescale foraging data with larger-scale spatial data. Given the accelerated rate of microcircuitry miniaturization, researchers may be able to obtain similar video images from all but the smallest of avian species in the near future. ACKNOWLEDGMENTS We thank the many assistants who helped maintain the cameras in the field, as well as the Missouri Department of Conservation for providing housing. We also thank the private land owners who granted us access to their property. We thank M. Ward, M. Alessi, H. Fraser, and D. Barron of INHS, and the Vermilion County Conservation District, particularly M. Pittman and K. Konsis, for assistance with the research in Illinois. We thank staff at the White River National Wildlife Refuge for logistical support. We thank P. J. Pietz, A. J. Pierce, and K. Sullivan for their reviews of this manuscript; their efforts greatly improved its quality. We thank the USDA Forest Service, the Audubon Society of Missouri, the Trans-World Airlines Scholarship program, the Illinois Department of Natural Resources, the Illinois Natural History Survey (INHS), the Arkansas Game and Fish Commission, and the U.S. Fish and Wildlife Service for funding the fieldwork for this project.

LITERATURE CITED Ben-Dov, A., Y. Vortman, and A. Lotem. 2006. First documentation of sibling cannibalism in a small passerine species. Ibis 148:365–367. Benson, T. J., J. D. Brown, and J. C. Bednarz. 2010. Identifying predators clarifies predictors of nest success in a temperate passerine. Journal of Animal Ecology 79:225–234. Bolton, M., N. Butcher, F. Sharpe, D. Stevens, and G. Fisher. 2007. Remote monitoring of nests using digital camera technology. Journal of Field Ornithology 78:213–220. Booms, T. L., and M. R. Fuller. 2003. Time-lapse video system used to study nesting Gyrfalcons. Journal of Field Ornithology 74:416–422.

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Brown, J., and S.D. Gehrt. 2009. The basics of using remote cameras to monitor wildlife. Ohio State University Extension Agriculture and Natural Resources Fact Sheet W-21-09. Ohio Sate University, Columbus, OH. Buler, J. J., and R. B. Hamilton. 2000. Predation of natural and artificial nests in a southern pine forest. Auk 117:739–747. Cartar, R. V., and R. D. Montgomerie. 1987. Day-today variation in nest attentiveness of White-rumped Sandpipers. Condor 89:252–260. Coates, P. S., J. W. Connelly, and D. J. Delehanty. 2008. Predators of Greater Sage-Grouse nests identified by video monitoring. Journal of Field Ornithology 79:421–428. Colombelli-Négrel, D., J. Robertson, and S. Kleindorfer. 2009. A new audio-visual technique for effectively monitoring nest predation and the behaviour of nesting birds. Emu 109:83–88. Conner, L. M., J. C. Rutledge, and L. L. Smith. 2010. Effects of mesopredators on nest survival of shrubnesting songbirds. Journal of Wildlife Management 74:73–80. Cutler, T. L., and D. E. Swann. 1999. Using remote photography in wildlife ecology: a review. Wildlife Society Bulletin 27:571–581. Dreibelbis, J. Z., K. B. Melton, R. Aguirre, B. A. Collier, J. Hardin, N. J. Silvy, and M. J. Peterson. 2008. Predation of Rio Grande Wild Turkey nests on the Edwards Plateau, Texas. Wilson Journal of Ornithology 120:906–910. Dyer, P. K., and G. J. E. Hill. 1991. A solution to the problem of determining the occupancy status of Wedge-tailed Shearwater Puffinus pacificus burrows. Emu 91:20–25. Gilbert, W. M., P. M. Nolan, A. M. Stoehr, and G. E. Hill. 2005. Filial cannibalism at a House Finch nest. Wilson Bulletin 117:413–415. Grivas, C., S. M. Xirouchakis, C. Christodoulou, B. Carcamo-Aboitiz, P. Georgiakakis, and M. Probonas. 2009. An audio-visual nest monitoring system for the study and manipulation of siblicide in Bearded Vultures Gypaetus barbatus on the island of Crete (Greece). Journal of Ethology 27:105–116. Grønnesby, S., and T. Nygård. 2000. Using time-lapse video monitoring to study prey selection by breeding Goshawks Accipiter gentilis in Central Norway. Ornis Fennica 77:117–129. Grundel, R. 1987. Determinants of nestling feeding rates and parental investment in the Mountain Chickadee. Condor 89:319–328. Guzy, M. J., C. A. Ribic, and D. W. Sample. 2002. Helping at a Henslow’s Sparrow nest in Wisconsin. Wilson Bulletin 114:407–409.

Gysel, L. W., and E. M. Davis, Jr. 1956. A simple automatic photographic unit for wildlife research. Journal of Wildlife Management 20:451–453. Hanula, J. L., and K. E. Franzreb. 1995. Arthropod prey of nestling Red-cockaded Woodpeckers in the upper coastal plain of South Carolina. Wilson Bulletin 107:485–495. Hernandez, F., D. Rollins, and R. Cantu. 1997. An evaluation of Trailmaster® camera systems for identifying ground-nest predators. Wildlife Society Bulletin 25:848–853. Herranz, J., M. Yanes, and F. Suárez. 2002. Does photo-monitoring affect nest predation? Journal of Field Ornithology 73:97–101. Honza, M., and C. Moskát. 2008. Egg rejection behaviour in the Great Reed Warbler (Acrocephalus arundinaceus): the effect of egg type. Journal of Ethology 26:389–395. Hudson, M. R., and D. M. Bird. 2006. An affordable computerized camera technique for monitoring bird nests. Wildlife Society Bulletin 34:1455–1457. Hussell, D. J. T. 1974. Photographic records of predation at Lapland Longspur and Snow Bunting nests. Canadian Field-Naturalist 88:503–506. King, D. I., R. M. DeGraaf, P. J. Champlin, and T. B. Champlin. 2001. A new method for wireless video monitoring of bird nests. Wildlife Society Bulletin 29:349–353. King, D. I., and R. M. DeGraaf. 2006. Predators at bird nests in a northern hardwood forest in New Hampshire. Journal of Field Ornithology 77:239–243. Liebezeit, J. R., and T. L. George. 2003. Comparison of mechanically egg-triggered cameras and timelapse video cameras in identifying predators at Dusky Flycatcher nests. Journal of Field Ornithology 74:261–269. Margalida, A., S. Ecolan, J. Boudet, J. Bertran, J. Martinez, and R. Heredia. 2006. A solar-powered transmitting video camera for monitoring cliff-nesting raptors. Journal of Field Ornithology 77:7–12. McRae, S. B., P. J. Weatherhead, and R. Montgomerie. 1993. American Robin nestlings compete by jockeying for position. Behavioral Ecology and Sociobiology 33:101–106. Momose, K., F. Sato, A. Kajita, and K. Saitou. 2003. Observations of breeding activity of Short-tailed Albatross Diomeda albatrus by satellite portable phone. Journal of the Yamashina Institute for Ornithology 34:314–319. Morris, A. J., and J. J. Gilroy. 2008. Close to the edge: predation risks for two declining farmland passerines. Ibis 150(Suppl. 1):168–177. Nathan, A., S. Legge, and A. Cockburn. 2001. Nestling aggression in broods of a siblicidal kingfisher, the Laughing Kookaburra. Behavioral Ecology 12:716–725.

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Pechacek, P. 2005. Use of non-stop video surveillance to monitor breeding activity of primary cavity nesters in remote areas. Acta Ethologica 8:1–4. Pierce, A. J., and K. Pobprasert. 2007. A portable system for continuous monitoring of bird nests using digital video recorders. Journal of Field Ornithology 78:322–328. Pietz, P. J., and D. A. Granfors. 2000. Identifying predators and fates of grassland passerine nests using miniature video cameras. Journal of Wildlife Management 64:71–87. Proudfoot, G. A. 1996. Miniature video-board camera used to inspect natural and artificial nest cavities. Wildlife Society Bulletin 24:528–530. Reif, V., and R. Tornberg. 2006. Using time-lapse digital video recording for a nesting study of birds of prey. European Journal of Wildlife Research 52:251–258. Richardson, T. W., T. Gardali, and S. H. Jenkins. 2009. Review and meta-analysis of camera effects on avian nest success. Journal of Wildlife Management 73:287–293. Royama, T. 1959. A device of an auto-cinematic foodrecorder. Tori 15:20–24. Rutz, C., L. A. Bluff, A. A. S. Weir, and A. Kacelnik. 2007. Video cameras on wild birds. Science 318:765–765. Sabine, J. B., J. M. Meyers, and S. H. Schweitzer. 2005. A simple, inexpensive video camera setup for the

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study of avian nest activity. Journal of Field Ornithology 76:293–297. Sanders, M. D., and R. F. Maloney. 2002. Causes of mortality at nests of ground-nesting birds in the Upper Waitaki Basin, South Island, New Zealand: a 5-year video study. Biological Conservation 106:225–236. Stake, M. M., and D. A. Cimprich. 2003. Using video to monitor predation at Black-capped Vireo nests. Condor 105:348–357. Stevens, D. K., G. Q. A. Anderson, P. V. Grice, K. Norris, and N. Butcher. 2008. Predators of Spotted Flycatcher Muscicapa striata nests in southern England as determined by digital nest-cameras. Bird Study 55:179–187. Thompson, F. R., III, and D. E. Burhans. 2003. Predation of songbird nests differs by predator and between field and forest habitats. Journal of Wildlife Management 67:408–416. Thompson, F. R., III, and D. E. Burhans. 2004. Differences in predators of artificial and real songbird nests: evidence of bias in artificial nest studies. Conservation Biology 18:373–380. Thompson, F. R., III, W. Dijak, and D. E. Burhans. 1999. Video identification of predators at songbird nests in old fields. Auk 116:259–264.

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APPENDIX 15.1

Studies Published During 1956–January 2009 That Used Camera Technology to Monitor Nests (Found Using Search Criteria Described in Methods)

Åhlund, M. 2005. Behavioural tactics at nest visits differ between parasites and hosts in a brood-parasitic duck. Animal Behaviour 70:433–440. Alvarez, A. D., and M. Galetti. 2007. Predação de ninhos artificiais em uma ilha na Mata Atlântica: testando o local e o tipo de ovo. Revista Brasileira de Zoologia 24:1011–1016. Ambagis, J. 2004. A comparison of census and monitoring techniques for Leach’s Storm Petrel. Waterbirds 27:211–215. Andersson, M., and M. Åhlund. 2001. Protein fingerprinting: a new technique reveals extensive conspecific brood parasitism. Ecology 82:1433–1442. Anthony, R. M., J. B. Grand, T. F. Fondell, and B. F. J. Manly. 2004. A quantitative approach to identifying predators from nest remains. Journal of Field Ornithology 75:40–48. Anthony, R. M., J. B. Grand, T. F. Fondell, and D. A. Miller. 2006. Techniques for identifying predators of goose nests. Wildlife Biology 12:249–256. Antonov, A., B. G. Stokke, A. Moksnes, and E. Røskaft. 2008. Getting rid of the cuckoo Cuculus canorus egg: why do hosts delay rejection? Behavioral Ecology 19:100–107. Ba nbura, ´ J., J. Blondel, H. de Wilde-Lambrechts, M. Galan, and M. Maistre. 1994. Nestling diet variation in an insular Mediterranean population of Blue Tits Parus caeruleus: effects of years, territories and individuals. Oecologia 100:413–420. Banbura, ´ J., P. Perret, J. Blondel, A. Sauvages, M. Galan, and M. M. Lambrechts. 2001. Sex differences in parental care in a Corsican Blue Tit Parus caeruleus population. Ardea 89:517–526. Barkley, W. D. 1972. The application of closed-circuit television to nature interpretation. Canadian FieldNaturalist 86:162. Barkow, A. 2005. Prädation an Singvogelnestern in Hecken: der Einfluss von Neststandort, Heckenstruktur, Jahreszeit und Prädatoren. Vogelwelt 126:346–352.

Bayne, E. M., and K. A. Hobson. 1997. Comparing the effects of landscape fragmentation by forestry and agriculture on predation of artificial nests. Conservation Biology 11:1418–1429. Bayne, E. M., and K. A. Hobson. 1999. Do clay eggs attract predators to artificial nests? Journal of Field Ornithology 70:1–7. Bayne, E. M., K. A. Hobson, and P. Fargey. 1997. Predation on artificial nests in relation to forest type: contrasting the use of quail and plasticine eggs. Ecography 20:233–239. Ben-Dov, A., Y. Vortman, and A. Lotem. 2006. First documentation of sibling cannibalism in a small passerine species. Ibis 148:365–367. Berry, L. 2002. Identifying nest-predator species in a southern Victorian woodland using remotely triggered cameras at artificial nests. Corella 26:24–26. Berry, L., and E. Taisacan. 2008. Nest success and nest predation of the endangered Rota White-eye (Zosterops rotensis). Wilson Journal of Ornithology 120:618–619. Birrer, S., and M. Hüsler. 2003. Ein Fall von Infantizid bei der Schleiereule (Tyto alba). Ornithologische Beobachter 100:143–146. Blondel, J., A. Dervieux, M. Maistre, and P. Perret. 1991. Feeding ecology and life history variation of the Blue Tit in Mediterranean deciduous and sclerophyllous habitats. Oecologia 88:9–14. Blondel, J., P. Isenmann, M. Maistre, and P. Perret. 1992. What are the consequences of being a downy oak (Quercus pubescens) or a holm oak (Q. ilex) for breeding Blue Tits (Parus caeruleus)? Vegetatio 99–100:129–136. Boland, C. R. J., and R. M. Phillips. 2005. A small, lightweight, and inexpensive “burrowscope” for viewing nest contents of tunnel-nesting birds. Journal of Field Ornithology 76:21–26. Bolton, M., N. Butcher, F. Sharpe, D. Stevens, and G. Fisher. 2007. Remote monitoring of nests using digital camera technology. Journal of Field Ornithology 78:213–220. 199

Booms, T. L., and M. R. Fuller. 2003a. Gyrfalcon diet in central west Greenland during the nesting period. Condor 105:528–537. Booms, T. L., and M. R. Fuller. 2003b. Gyrfalcon feeding behavior during the nestling period in central west Greenland. Arctic 56:341–348. Booms, T. L., and M. R. Fuller. 2003c. Time-lapse video system used to study nesting Gyrfalcons. Journal of Field Ornithology 74:416–422. Booth, A. M., E. O. Minot, R. A. Fordham, and J. G. Innes. 1996. Kiore (Rattus exulans) predation on the eggs of the Little Shearwater (Puffinus assimilis haurakiensis). Notornis 43:147–153. Bouwman, K. M., C. M. Lessells, and J. Komdeur. 2005. Male Reed Buntings do not adjust parental effort in relation to extrapair paternity. Behavioral Ecology 16:499–506. Bradley, J. E., and J. M. Marzluff. 2003. Rodents as nest predators: influences on predatory behavior and consequences to nesting birds. Auk 120:1180–1187. Brown, K., J. Innes, and R. Shorten. 1993. Evidence that possums prey on and scavenge birds’ eggs, birds and mammals. Notornis 40:169–177. Brown, K. P., H. Moller, J. Innes, and P. Jansen. 1998. Identifying predators at nests of small birds in a New Zealand forest. Ibis 140:274–279. Budden, A. E., and J. Wright. 2000. Nestling diet, chick growth and breeding success in the Southern Grey Shrike (Lanius meridionalis). The Ring 22:165–172. Bühler, P., and W. Epple. 1980. Die Lautäußerungen der Schleiereule (Tyto alba). Journal of Ornithology 121:36–70. Buler, J. J., and R. B. Hamilton. 2000. Predation of natural and artificial nests in a southern pine forest. Auk 117:739–747. Byars, T., and D. J. Curtis. 1998. Feeding studies of the Lesser Whitethroat in Strathclyde. Scottish Birds 19:223–230. Cain, J. W., III, M. L. Morrison, and H. L. Bombay. 2003. Predator activity and nest success of Willow Flycatchers and Yellow Warblers. Journal of Wildlife Management 67:600–610. Caldwell, P. J., and G. W. Cornwell. 1975. Incubation behavior and temperatures of the Mallard duck. Auk 92:706–731. Canestrari, D., J. M. Marcos, and V. Baglione. 2004. False feedings at the nests of Carrion Crows Corvus corone corone. Behavioral Ecology and Sociobiology 55:477–483. Canestrari, D., J. M. Marcos, and V. Baglione. 2005. Effect of parentage and relatedness on the individual contribution to cooperative chick care in Carrion Crows Corvus corone corone. Behavioral Ecology and Sociobiology 57:422–428. Canestrari, D., J. M. Marcos, and V. Baglione. 2008. Reproductive success increases with group size in

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cooperative Carrion Crows, Corvus corone corone. Animal Behaviour 75:403–416. Cartar, R. V., and R. D. Montgomerie. 1987. Day-today variation in nest attentiveness of White-rumped Sandpipers. Condor 89:252–260. Carter, G. M., M. L. Legare, D. R. Breininger, and D. M. Oddy. 2007. Nocturnal nest predation: a potential obstacle to recovery of a Florida ScrubJay population. Journal of Field Ornithology 78:390–394. Challet, E., C. A. Bost, Y. Handrich, J. P. Gendner, and Y. Le Maho. 1994. Behavioural time budget of breeding King Penguins (Aptenodytes patagonica). Journal of Zoology 233:669–681. Coates, P. S., J. W. Connelly, and D. J. Delehanty. 2008. Predators of Greater Sage-Grouse nests identified by video monitoring. Journal of Field Ornithology 79:421–428. Collins, L., and D. B. Croft. 2007. Factors influencing chick survival in the Wedge-tailed Eagle Aquila audax. Corella 31:32–40. Cooper, J. A., and A. D. Afton. 1981. A multiple sensor system for monitoring avian nesting behavior. Wilson Bulletin 93:325–333. Cooper, S. M., and T. F. Ginnett. 2000. Potential effects of supplemental feeding of deer on nest predation. Wildlife Society Bulletin 28:660–666. Cotterill, S. E., and S. J. Hannon. 1999. No evidence of short-term effects of clear-cutting on artificial nest predation in boreal mixedwood forests. Canadian Journal of Forest Research 29:1900–1910. Cowie, R. J., and S. A. Hinsley. 1988a. Timing of return with green vegetation by nesting Blue Tits Parus caeruleus. Ibis 130:553–555. Cowie, R. J., and S. A. Hinsley. 1988b. Feeding ecology of Great Tits (Parus major) and Blue Tits (Parus caeruleus), breeding in suburban gardens. Journal of Animal Ecology 57:611–626. Craig, G. H., and J. L. Craig. 1974. An automatic nest recorder. Ibis 116:557–561. Craig, J. L. 1980. Pair and group breeding behaviour of a communal gallinule, the Pukeko Porphyrio p. melanotus. Animal Behaviour 28:593–603. Craig, J. L., and I. G. Jamieson. 1985. The relationship between presumed gamete contribution and parental investment in a communally breeding bird. Behavioral Ecology and Sociobiology 17:207–211. Currie, D., R. Bristol, J. Millett, and N. J. Shah. 2005. Demography of the Seychelles Black Paradise-Flycatcher: considerations for conservation and reintroduction. Ostrich 76:104–110. Currie, D., M. Hill, T. Vel, R. Fanchette, and C. Hoareau. 2003. Diet of the critically endangered Seychelles Scops Owl, Otus insularis. Ostrich 74:205–208. Custer, T. W. 1973. Snowy Owl predation on Lapland Longspur nestlings recorded on film. Auk 90:433–435. Dahlsten, D. L., and W. A. Copper. 1979. The use of nesting boxes to study the biology of the Mountain

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Chickadee (Parus gambeli) and its impact on selected forest insects. Pp. 217–260 in J. G. Dickson, R. N. Connor, R. R. Fleet, J. C. Croll, and J. A. Jackson (editors), The role of insectivorous birds in forest ecosystems. Academic Press, New York, NY. Danielson, W. R., R. M. DeGraaf, and T. K. Fuller. 1996. An inexpensive compact automatic camera system for wildlife research. Journal of Field Ornithology 67:414–421. Dearborn, D. C. 1996. Video documentation of a Brownheaded Cowbird nestling ejecting an Indigo Bunting nestling from the nest. Condor 98:645–649. Dearborn, D. C. 1998. Begging behavior and food acquisition by Brown-headed Cowbird nestlings. Behavioral Ecology and Sociobiology 43:259–270. DeGraaf, R. M. 1995. Nest predation rates in managed and reserved extensive northern hardwood forests. Forest Ecology and Management 79:227–234. Delaney, D. K., T. G. Grubb, and P. Beier. 1999. Activity patterns of nesting Mexican Spotted Owls. Condor 101:42–49. Delaney, D. K., T. G. Grubb, and D. K. Garcelon. 1998. An infrared video camera system for monitoring diurnal and nocturnal raptors. Journal of Raptor Research 32:290–296. Derksen, D. V. 1977. A quantitative analysis of the incubation behavior of the Adélie Penguin. Auk 94:552–566. DeVault, T. L., M. B. Douglas, J. S. Castrale, C. E. Mills, T. Hayes, and O. E. Rhodes, Jr. 2005. Identification of nest predators at a Least Tern colony in southwestern Indiana. Waterbirds 28:445–449. Durant, J. M., J. Gendner, and Y. Handrich. 2004. Should I brood or should I hunt: a female Barn Owl’s dilemma. Canadian Journal of Zoology 82:1011–1016. Dyer, P. K., and K. Aldworth. 1998. The “burrowscope”: modifications to burrow viewing equipment. Emu 98:143–146. Dyer, P. K., and G. J. E. Hill. 1991. A solution to the problem of determining the occupancy status of Wedge-tailed Shearwater Puffinus pacificus burrows. Emu 91:20–25. Dykstra, C. R., M. W. Meyer, and D. K. Warnke. 2002. Bald Eagle reproductive performance following video camera placement. Journal of Raptor Research 36:136–139. Edwards, S., E. Messenger, and K. Yasukawa. 1999. Do Red-winged Blackbird parents and their nestlings recognize each other? Journal of Field Ornithology 70:297–309. Eggers, S., M. Griesser, T. Andersson, and J. Ekman. 2005a. Nest predation and habitat change interact to influence Siberian Jay numbers. Oikos 111:150–158. Eggers, S., M. Griesser, and J. Ekman. 2005b. Predatorinduced plasticity in nest visitation rates in the Siberian Jay (Perisoreus infaustus). Behavioral Ecology 16:309–315.

Ellis-Felege, S. N., J. S. Burnam, W. E. Palmer, D. C. Sisson, S. D. Wellendorf, R. P. Thornton, H. L. Stribling, and J. P. Carroll. 2008. Cameras identify white-tailed deer depredating Northern Bobwhite nests. Southeastern Naturalist 7:562–564. Enderson, J. H., S. A. Temple, and L. G. Swartz. 1972. Time-lapse photographic records of nesting Peregrine Falcons. Living Bird 11:113–128. Enkerlin-Hoeflich, E. C., J. M. Packard, and J. J. González-Elizondo. 1999. Safe field techniques for nest inspections and nestling crop sampling of parrots. Journal of Field Ornithology 70:8–17. Fargallo, J. A., T. Laaksonen, E. Korpimäki, V. Pöyri, S. C. Griffith, and J. Valkama. 2003. Size-mediated dominance and begging behaviour in Eurasian Kestrel broods. Evolutionary Ecology Research 5:549–558. Farnsworth, G. L., and T. R. Simons. 2000. Observations of Wood Thrush nest predators in a large contiguous forest. Wilson Bulletin 112:82–87. Fenske-Crawford, T. J., and G. J. Niemi. 1997. Predation of artificial ground nests at two types of edges in a forest-dominated landscape. Condor 99:14–24. Ferretti, V., P. E. Llambías, and T. E. Martin. 2005. Life-history variation of a neotropical thrush challenges food limitation theory. Proceedings of the Royal Society of London, Series B 272:769–773. Fiorini, V. D., and F. L. Rabuffetti. 2003. Cuidado parental en el Churrinche (Pyrocephalus rubinus): contribución relativa del macho y de la hembra. Hornero 18:31–35. Flörchinger, S. 2002. Feldsperlinge (Passer montanus) entfernen Eier aus eigenen Nestern. Vogelwarte 41:279–282. Forsman, J. T., and R. L. Thomson. 2008. Evidence of information collection from heterospecifics in cavity-nesting birds. Ibis 150:409–412. Franzreb, K. E. 2007. Reproductive success and nest depredation of the Florida Scrub-Jay. Wilson Journal of Ornithology 119:162–169. Franzreb, K. E., and J. L. Hanula. 1995. Evaluation of photographic devices to determine nestling diet of the endangered Red-cockaded Woodpecker. Journal of Field Ornithology 66:253–259. Freitag, A. 2000. La photographie des nourrissages: une technique originale d’étude du régime alimentaire des jeunes torcols fourmiliers Jynx torquilla. Alauda 68:81–93. Friesen, L. E., C. Zantinge, and H. Britton. 2007. Presence of Wood Thrushes at a nest does not deter parasitism by Brown-headed Cowbirds. Wilson Journal of Ornithology 119:490–493. Fulton, G. R. 2006. Identification of nest predators with remote cameras and artificial nests in extensive old-growth woodland of southwestern Australia. Corella 30:35–39.

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Garcia, V., and C. J. Conway. 2009. Use of video probe does not affect Burrowing Owl reproductive parameters or return rates. Journal of Wildlife Management 73:154–157. Gilbert, A. T., and F. A. Servello. 2005. Insectivory versus piscivory in Black Terns: implications for food provisioning and growth of chicks. Waterbirds 28:436–444. Gilbert, W. M., P. M. Nolan, A. M. Stoehr, and G. E. Hill. 2005. Filial cannibalism at a House Finch nest. Wilson Bulletin 117:413–415. Giovanni, M. D., C. W. Boal, and H. A. Whitlaw. 2007. Prey use and provisioning rates of breeding Ferruginous and Swainson’s Hawks on the southern Great Plains, USA. Wilson Journal of Ornithology 119:558–569. Goetz, R. C. 1981. A photographic system for multiple automatic exposures under field conditions. Journal of Wildlife Management 45:273–276. Goodale, W., L. Attix, and D. Evers. 2005. Common Loon, Gavia immer, nest attendance patterns recorded by remote video camera. Canadian Field-Naturalist 119:455–456. Goodbred, C. O., and R. T. Holmes. 1996. Factors affecting food provisioning of nestling Black-throated Blue Warblers. Wilson Bulletin 108:467–479. Gorman, L. R., D. K. Rosenberg, N. A. Ronan, K. L. Haley, J. A. Gervais, and V. Franke. 2003. Estimation of reproductive rates of Burrowing Owls. Journal of Wildlife Management 67:493–500. Granfors, D. A., P. J. Pietz, and L. A. Joyal. 2001. Frequency of egg and nestling destruction by female Brown-headed Cowbirds at grassland nests. Auk 118:765–769. Grant, T. A., E. M. Madden, T. L. Shaffer, P. J. Pietz, G. B. Berkey, and N. J. Kadrmas. 2006. Nest survival of Clay-colored and Vesper Sparrows in relation to woodland edge in mixed-grass prairies. Journal of Wildlife Management 70:691–701. Griebel, R. L., and J. A. Savidge. 2007. Factors influencing Burrowing Owl reproductive performance in contiguous shortgrass prairie. Journal of Raptor Research 41:212–221. Griffing, S. M., A. M. Kilpatrick, L. Clark, and P. P. Marra. 2007. Mosquito landing rates on nesting American Robins (Turdus migratorius). VectorBorne and Zoonotic Diseases 7:437–443. Grivas, C., S. M. Xirouchakis, C. Christodoulou, B. Carcamo-Aboitiz, P. Georgiakakis, and M. Probonas. 2009. An audio-visual nest monitoring system for the study and manipulation of siblicide in Bearded Vultures Gypaetus barbatus on the island of Crete (Greece). Journal of Ethology 27:105–116. Grønnesby, S., and T. Nygård. 2000. Using time-lapse video monitoring to study prey selection by breeding Goshawks Accipiter gentilis in Central Norway. Ornis Fennica 77:117–129. Grundel, R. 1987. Determinants of nestling feeding rates and parental investment in the Mountain Chickadee. Condor 89:319–328. 202

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Grundel, R. 1990. The role of dietary diversity, prey capture sequence and individuality in prey selection by parent Mountain Chickadees (Parus gambeli). Journal of Animal Ecology 59:959–976. Grundel, R. 1992. How the Mountain Chickadee procures more food in less time for its nestlings. Behavioral Ecology and Sociobiology 31:291–300. Grundel, R., and D. L. Dahlsten. 1991. The feeding ecology of Mountain Chickadees (Parus gambeli): patterns of arthropod prey delivery to nestling birds. Canadian Journal of Zoology 69:1793–1804. Guthery, F. S., A. R. Rybak, S. D. Fuhlendorf, T. L. Hiller, S. G. Smith, W. H. Puckett, Jr., and R. A. Baker. 2005. Aspects of the thermal ecology of Bobwhites in North Texas. Wildlife Monographs No. 159. Guzy, M. J., C. A. Ribic, and D. W. Sample. 2002. Helping at a Henslow’s Sparrow nest in Wisconsin. Wilson Bulletin 114:407–409. Gysel, L. W., and E. M. Davis, Jr. 1956. A simple automatic photographic unit for wildlife research. Journal of Wildlife Management 20:451–453. Haftorn, S. 1972. Internt fjernsyn og datalogger i ornitologiens tjeneste. Sterna 11:243–252. Haftorn, S. 2002. Observations at a nest of the Chiffchaff Phylloscopus collybita by means of closedcircuit television. Ornis Norvegica 25:52–56. Hamilton, S. 1998. Determining burrow occupancy, fledging success and land-based threats to mainland and near-shore island Sooty Shearwater (Puffinus griseus) colonies. New Zealand Journal of Zoology 25:443–453. Hamilton, S. 2000. How precise and accurate are data obtained using an infra-red scope on burrownesting Sooty Shearwaters Puffinus griseus? Marine Ornithology 28:1–6. Hampl, R., S. Bures, P. Baláz, M. Bobek, and F. Pojer. 2005. Food provisioning and nestling diet of the Black Stork in the Czech Republic. Waterbirds 28:35–40. Hanula, J. L., and K. E. Franzreb. 1995. Arthropod prey of nestling Red-cockaded Woodpeckers in the upper coastal plain of South Carolina. Wilson Bulletin 107:485–495. Hanula, J. L., D. Lipscomb, K. E. Franzreb, and S. C. Loeb. 2000. Diet of nestling Red-cockaded Woodpeckers at three locations. Journal of Field Ornithology 71:126–134. Hario, M., and E. Rudbäck. 1999. Dying in the midst of plenty: the third-chick fate in nominate Lesser Black-backed Gulls Larus f. fuscus. Ornis Fennica 76:71–77. Hauber, M. E. 1998. Single-egg removal from an artificial nest by the Gray Catbird. Wilson Bulletin 110:426–429. Hauber, M. E., and K. Montenegro. 2002. What are the costs of raising a brood parasite? Comparing host parental care at parasitized and non-parasitized broods. Etologia 10:1–9.

NO. 43

Ribic, Thompson, and Pietz

Hauber, M. E., and C. Moskát. 2008. Shared parental care is costly for nestlings of Common Cuckoos and their Great Reed Warbler hosts. Behavioral Ecology 19:79–86. Hébert, P. N., H. R. Carter, R. T. Golightly, and D. L. Orthmeyer. 2003. Radio-telemetry evidence of renesting in the same season by the Marbled Murrelet. Waterbirds 26:261–265. Hébert, P. N., and R. T. Golightly. 2007. Observations of predation by corvids at a Marbled Murrelet nest. Journal of Field Ornithology 78:221–224. Hernandez, F., D. Rollins, and R. Cantu. 1997a. Evaluating evidence to identify ground-nest predators in west Texas. Wildlife Society Bulletin 25:826–831. Hernandez, F., D. Rollins, and R. Cantu. 1997b. An evaluation of Trailmaster® camera systems for identifying ground-nest predators. Wildlife Society Bulletin 25:848–853. Hernández, M. A., A. Martín, and M. Nogales. 1999. Breeding success and predation on artificial nests of the endemic pigeons Bolle’s Laurel Pigeon Columba bollii and White-tailed Laurel Pigeon Columba junoniae in the laurel forest of Tenerife (Canary Islands). Ibis 141:52–59. Herranz, J., M. Yanes, and F. Suárez. 2002. Does photo-monitoring affect nest predation? Journal of Field Ornithology 73:97–101. Hill, I. F., B. Cresswell, and R. E. Kenward. 1999a. Comparison of brooding patterns between Blackbird Turdus merula and Song Thrush T. philomelos. Bird Study 46:122–126. Hill, I. F., B. H. Cresswell, and R. E. Kenward. 1999b. Field-testing the suitability of a new back-pack harness for radio-tagging passerines. Journal of Avian Biology 30:135–142. Hirons, G. J. M. 1985. The importance of body reserves for successful reproduction in the Tawny Owl (Strix aluco). Journal of Zoology, Series B 1:1–20. Holmes, S. B. 1998. Reproduction and nest behaviour of Tennessee Warblers Vermivora peregrina in forests treated with Lepidoptera-specific insecticides. Journal of Applied Ecology 35:185–194. Honza, M., T. Grim, M. Capek, Jr., A. Moksnes, and E. Røskaft. 2004. Nest defence, enemy recognition and nest inspection behaviour of experimentally parasitized Reed Warblers Acrocephalus scirpaceus. Bird Study 51:256–263. Honza, M., and C. Moskát. 2008. Egg rejection behaviour in the Great Reed Warbler (Acrocephalus arundinaceus): the effect of egg type. Journal of Ethology 26:389–395. Honza, M., K. Voslajerová, and C. Moskát. 2007. Eviction behaviour of the Common Cuckoo Cuculus canorus chicks. Journal of Avian Biology 38:385–389. Hoover, A. K., F. C. Rohwer, and K. D. Richkus. 2004. From the field: evalution of nest temperatures to assess female nest attendance and use of video cameras to monitor incubating waterfowl. Wildlife Society Bulletin 32:581–587.

Hudson, M. R., and D. M. Bird. 2006. An affordable computerized camera technique for monitoring bird nests. Wildlife Society Bulletin 34:1455–1457. Huebner, D. P., and S. R. Hurteau. 2007. An economical wireless cavity-nest viewer. Journal of Field Ornithology 78:87–92. Hussell, D. J. T. 1972. Factors affecting clutch size in arctic passerines. Ecological Monographs 42:317– 364. Hussell, D. J. T. 1974. Photographic records of predation at Lapland Longspur and Snow Bunting nests. Canadian Field-Naturalist 88:503–506. Innes, J., G. Nugent, K. Prime, and E. B. Spurr. 2004. Responses of Kukupa (Hemiphaga novaeseelandiae) and other birds to mammal pest control at Motatau, Northland. New Zealand Journal of Ecology 28:73–81. Jenkins, M. A. 1978. Gyrfalcon nesting behavior from hatching to fledging. Auk 95:122–127. Johansen, H. M., V. Selås, K. Fagerland, J. T. Johnsen, B. A. Sveen, L. Tapia, and R. Steen. 2007. Goshawk diet during the nestling period in farmland and forest-dominated areas in southern Norway. Ornis Fennica 84:181–188. Johnston, R. B., S. M. Bettany, R. M. Ogle, H. A. Aikman, G. A. Taylor, and M. J. Imber. 2003. Breeding and fledging behaviour of the Chatham Taiko (Magenta Petrel) Pterodroma magentae, and predator activity at burrows. Marine Ornithology 31:193–197. Jongbloed, F., H. Schekkerman, and W. Teunissen. 2006. Verdeling van de broedinspanning bij Kieviten. Limosa 79:63–70. Kaiser, M. 2004. Die erfolgreiche Zucht des Kampfadlers, Polemaetus bellicosus (Daudin, 1800), im Tierpark Berlin-Friedrichsfelde. Zoologische Garten 74:307–327. Kameda, K. 1994. Identification of nest predators of the Rufous Turtle Dove Streptopelia orientalis by video tape recording. Japanese Journal of Ornithology 43:29–31. Keedwell, R. J. 2005. Breeding biology of Black-fronted Terns (Sterna albostriata) and the effects of predation. Emu 105:39–47. Keedwell, R. J., and M. D. Sanders. 2002. Nest monitoring and predator visitation at nests of Banded Dotterels. Condor 104:899–902. Kershner, E. L., and E. C. Mruz. 2006. Nest interference by fledgling Loggerhead Shrikes. Wilson Journal of Ornithology 118:75–80. King, D. I., and R. M. DeGraaf. 2006. Predators at bird nests in a northern hardwood forest in New Hampshire. Journal of Field Ornithology 77:239–243. King, D. I., R. M. DeGraaf, P. J. Champlin, and T. B. Champlin. 2001. A new method for wireless video monitoring of bird nests. Wildlife Society Bulletin 29:349–353. Kirkpatrick, C., and C. J. Conway. 2006. Woodrat (Neotoma) depredation of a Yellow-eyed Junco

NEST CAMERA TECHNOLOGY

203

(Junco phaeonotus) nest. Southwestern Naturalist 51:412–414. Kleiber, D., J. Turner, A. E. Budden, and J. L. Dickinson. 2007. Interspecific egg-dumping by a Violetgreen Swallow in an active Western Bluebird nest. Wilson Journal of Ornithology 119:126–128. Kleintjes, P. K., and D. L. Dahlsten. 1992. A comparison of three techniques for analyzing the arthropod diet of Plain Titmouse and Chestnut-backed Chickadee nestlings. Journal of Field Ornithology 63:276–285. Kleintjes, P. K., and D. L. Dahlsten. 1994. Foraging behavior and nestling diet of Chestnut-backed Chickadees in Monterey pine. Condor 96:647–653. Knapton, R. W. 1980. Nestling foods and foraging patterns in the Clay-colored Sparrow. Wilson Bulletin 92:458–465. Kochanek, H. 1990. Ernährung des Turmfalken (Falco tinnunculus): Ergebnisse von Nestinhaltsanalysen und automatischer Registrierung. Journal of Ornithology 131:291–304. Kofoed, E. M., and S. K. Auer. 2004. First description of the nest, eggs, young, and breeding behavior of the Great Antpitta (Grallaria excelsa). Wilson Bulletin 116:105–108. Kölliker, M., and H. Richner. 2004. Navigation in a cup: chick positioning in Great Tit, Parus major, nests. Animal Behaviour 68:941–948. Kristan, D. M., R. T. Golightly, Jr., and S. M. Tomkiewicz Jr. 1996. A solar-powered transmitting video camera for monitoring raptor nests. Wildlife Society Bulletin 24:284–290. Langston, R. H. W., D. Liley, G. Murison, E. Woodfield, and R. T. Clarke. 2007. What effects do walkers and dogs have on the distribution and productivity of breeding European Nightjar Caprimulgus europaeus? Ibis 149(Suppl. 1):27–36. Larson, K., and D. Craig. 2006. Digiscoping vouchers for diet studies in bill-load holding birds. Waterbirds 29:198–202. Latif, Q. S., J. L. Grenier, S. K. Heath, G. Ballard, and M. E. Hauber. 2006. First evidence of conspecific brood parasitism and egg ejection in Song Sparrows, with comments on methods sufficient to document these behaviors. Condor 108:452–458. Laurance, W. F., and J. D. Grant. 1994. Photographic identification of ground-nest predators in Australian tropical rainforest. Wildlife Research 21:241–248. Laut, M. E., P. C. Banko, and E. M. Gray. 2003. Nesting behavior of Palila, as assessed from video recordings. Pacific Science 57:385–392. Leimgruber, P., and B. K. Gupta. 2001. A comparison of identification techniques for predators on artificial nests. Tigerpaper 28:20–23. Leimgruber, P., W. J. McShea, and J. H. Rappole. 1994. Predation on artificial nests in large forest blocks. Journal of Wildlife Management 58:254–260.

204

STUDIES IN AVIAN BIOLOGY

Lewis, S. B., P. DeSimone, K. Titus, and M. R. Fuller. 2004a. A video surveillance system for monitoring raptor nests in a temperate rainforest environment. Northwest Science 78:70–74. Lewis, S. B., M. R. Fuller, and K. Titus. 2004b. A comparison of 3 methods for assessing raptor diet during the breeding season. Wildlife Society Bulletin 32:373–385. Lewis, S. B., K. Titus, and M. R. Fuller. 2006. Northern Goshawk diet during the nesting season in southeast Alaska. Journal of Wildlife Management 70:1151–1160. Lichtenstein, G. 2001. Low success of Shiny Cowbird chicks parasitizing Rufous-bellied Thrushes: chick– chick competition or parental discrimination? Animal Behaviour 61:401–413. Lichtenstein, G., and D. C. Dearborn. 2004. Begging and short-term need in cowbird nestlings: how different are brood parasites? Behavioral Ecology and Sociobiology 56:352–359. Liebezeit, J. R., and T. L. George. 2002. Nest predators, nest-site selection, and nesting success of the Dusky Flycatcher in a managed ponderosa pine forest. Condor 104:507–517. Liebezeit, J. R., and T. L. George. 2003. Comparison of mechanically egg-triggered cameras and timelapse video cameras in identifying predators at Dusky Flycatcher nests. Journal of Field Ornithology 74:261–269. Liebezeit, J. R., and S. Zack. 2008. Point counts underestimate the importance of arctic foxes as avian nest predators: evidence from remote video cameras in arctic Alaskan oil fields. Arctic 61:153–161. Luginbuhl, J. M., J. M. Marzluff, J. E. Bradley, M. G. Raphael, and D. E. Varland. 2001. Corvid survey techniques and the relationship between corvid relative abundance and nest predation. Journal of Field Ornithology 72:556–572. Lusk, J. J., S. G. Smith, S. D. Fuhlendorf, and F. S. Guthery. 2006. Factors influencing Northern Bobwhite nest-site selection and fate. Journal of Wildlife Management 70:564–571. Maier, T. J., and R. M. DeGraaf. 2000a. Rhodamineinjected eggs to photographically identify small nestpredators. Journal of Field Ornithology 71:694–701. Maier, T. J., and R. M. DeGraaf. 2000b. Predation on Japanese Quail vs. House Sparrow eggs in artificial nests: small eggs reveal small predators. Condor 102:325–332. Major, R. E. 1991. Identification of nest predators by photography, dummy eggs, and adhesive tape. Auk 108:190–195. Major, R. E., F. J. Christie, G. Gowing, and T. J. Ivison. 1999. Elevated rates of predation on artificial nests in linear strips of habitat. Journal of Field Ornithology 70:351–364. Major, R. E., and G. Gowing. 1994. An inexpensive photographic technique for identifying nest

NO. 43

Ribic, Thompson, and Pietz

predators at active nests of birds. Wildlife Research 21:657–666. Maloney, R. F. 1998. Video monitoring observations of a Houbara Bustard Chlamydotis undulata nest in Mahazat as-Sayd Reserve, central Saudi Arabia. Sandgrouse 20:36–39. Malt, J., and D. Lank. 2007. Temporal dynamics of edge effects on nest predation risk for the Marbled Murrelet. Biological Conservation 140:160–173. Mankin, P. C., and R. E. Warner. 1992. Vulnerability of ground nests to predation on an agricultural habitat island in east-central Illinois. American Midland Naturalist 128:281–291. Margalida, A., J. Bertran, and J. Boudet. 2005. Assessing the diet of nestling Bearded Vultures: a comparison between direct observation methods. Journal of Field Ornithology 76:40–45. Margalida, A., J. Boudet, R. Heredia, and J. Bertran. 2002. Videocámaras para la monitorización de la nidificación del Quebrantahuesos (Gypaetus barbatus). Ecología 16:325–333. Margalida, A., S. Ecolan, J. Boudet, J. Bertran, J. Martinez, and R. Heredia. 2006. A solar-powered transmitting video camera for monitoring cliffnesting raptors. Journal of Field Ornithology 77:7–12. Markham, A. C., and B. D. Watts. 2008. The influence of salinity on the diet of nesting Bald Eagles. Journal of Raptor Research 42:99–109. Markwell, T. J. 1997. Video camera count of burrowdwelling Fairy Prions, Sooty Shearwaters, and Tuatara on Takapourewa (Stephens Island), New Zealand. New Zealand Journal of Zoology 24:231–237. Martin, T. E., and C. K. Ghalambor. 1999. Males feeding females during incubation, I: Required by microclimate or constrained by nest predation? American Naturalist 153:131–139. Marzluff, J. M., M. G. Raphael, and R. Sallabanks. 2000. Understanding the effects of forest management on avian species. Wildlife Society Bulletin 28:1132–1143. Mattsson, B. J., J. M. Meyers, and R. J. Cooper. 2006. Detrimental impacts of radiotransmitters on juvenile Louisiana Waterthrushes. Journal of Field Ornithology 77:173–177. Maurel, C., and S. Poustomis. 2001. L’étude de l’alimentation au nid des jeunes busards Saint-Martin Circus cyaneus et cendrés Circus pygargus par suivi vidéo. Alauda 69:239–254. McCallum, C. A., and S. J. Hannon. 2001. Accipiter predation of American Redstart nestlings. Condor 103:192–194. McCarty, J. P. 2002. The number of visits to the nest by parents is an accurate measure of food delivered to nestlings in Tree Swallows. Journal of Field Ornithology 73:9–14. McGowan, C. P., and T. R. Simons. 2006. Effects of human recreation on the incubation behavior of

American Oystercatchers. Wilson Journal of Ornithology 118:485–493. McQuillen, H. L., and L. W. Brewer. 2000. Methodological considerations for monitoring wild bird nests using video technology. Journal of Field Ornithology 71:167–172. McRae, S. B., P. J. Weatherhead, and R. Montgomerie. 1993. American Robin nestlings compete by jockeying for position. Behavioral Ecology and Sociobiology 33:101–106. Meckstroth, A. M., and A. K. Miles. 2005. Predator removal and nesting waterbird success at San Francisco Bay, California. Waterbirds 28:250–255. Mennechez, G., and P. Clergeau. 1999. Une microcaméra pour inspecter les nids et les cavités. Revue d’Ecologie: La Terre et la Vie 54:189–191. Minot, E. O. 1981. Effects of interspecific competition for food in breeding Blue and Great Tits. Journal of Animal Ecology 50:375–385. Moksnes, A., E. Røskaft, L. G. Hagen, M. Honza, C. Mørk, and P. H. Olsen. 2000. Common Cuckoo Cuculus canorus and host behaviour at Reed Warbler Acrocephalus scirpaceus nests. Ibis 142:247–258. Momose, K., F. Sato, A. Kajita, and K. Saitou. 2003. Observations of breeding activity of Short-tailed Albatross Diomeda albatrus by satellite portable phone. Journal of the Yamashina Institute for Ornithology 34:314–319. Montalbano, F., III, P. W. Glanz, M. W. Olinde, and L. S. Perrin. 1985. A solar-powered time-lapse camera to record wildlife activity. Wildlife Society Bulletin 13:178–182. Moreno, J., R. J. Cowie, J. J. Sanz, and R. S. R. Williams. 1995. Differential response by males and females to brood manipulations in the Pied Flycatcher: energy expenditure and nestling diet. Journal of Animal Ecology 64:721–732. Moreno, J., J. J. Sanz, and E. Arriero. 1999. Reproductive effort and T-lymphocyte cell-mediated immunocompetence in female Pied Flycatchers Ficedula hypoleuca. Proceedings of the Royal Society of London, Series B 266:1105–1109. Moreno-Rueda, G., M. Soler, J. J. Soler, J. G. Martínez, and T. Pérez-Contreras. 2007. Rules of food allocation between nestlings of the Black-billed Magpie Pica pica, a species showing brood reduction. Ardeola 54:15–25. Morgan, D., J. R. Waas, and J. Innes. 2006. The relative importance of Australian magpies (Gymnorhina tibicen) as nest predators of rural birds in New Zealand. New Zealand Journal of Zoology 33:17–29. Morris, A. J., and J. J. Gilroy. 2008. Close to the edge: predation risks for two declining farmland passerines. Ibis 150(Suppl. 1):168–177. Morrison, S. A., and D. T. Bolger. 2002. Lack of an urban edge effect on reproduction in a fragmentation-sensitive sparrow. Ecological Applications 12:398–411.

NEST CAMERA TECHNOLOGY

205

Moser, A. M., and J. T. Ratti. 2005. Value of riverine islands to nongame birds. Wildlife Society Bulletin 33:273–284. Nachtigall, W. 1996. Flugverhalten der Kohlmeise Parus major am Nistkasten: Möglichkeiten und Grenzen von Vogelfluganalysen durch Camcorder mit Hochgeschwindigkeitsverschluß. Journal für Ornithologie 137:463–477. Nathan, A., S. Legge, and A. Cockburn. 2001. Nestling aggression in broods of a siblicidal kingfisher, the Laughing Kookaburra. Behavioral Ecology 12:716–725. Neuenschwander, S., M. W. G. Brinkhof, M. Kölliker, and H. Richner. 2003. Brood size, sibling competition, and the cost of begging in Great Tits (Parus major). Behavioral Ecology 14:457–462. Nolan, P. M., A. M. Stoehr, G. E. Hill, and K. J. McGraw. 2001. The number of provisioning visits by House Finches predicts the mass of food delivered. Condor 103:851–855. Novácek, M., and K. Hudec. 1961. Analysis of the food of the starling by remote-control photography. Medical and Biological Illustration 11:172–177. Ouchley, K., R. B. Hamilton, and S. Wilson. 1994. Nest monitoring using a micro-video camera. Journal of Field Ornithology 65:410–412. Pechacek, P. 2005. Use of non-stop video surveillance to monitor breeding activity of primary cavity nesters in remote areas. Acta Ethologica 8:1–4. Perkins, A. J., M. H. Hancock, N. Butcher, and R. W. Summers. 2005. Use of time-lapse video cameras to determine causes of nest failure of Slavonian Grebes Podiceps auritus. Bird Study 52:159–165. Peterson, B. L., B. E. Kus, and D. H. Deutschman. 2004. Determining nest predators of the Least Bell’s Vireo through point counts, tracking stations, and video photography. Journal of Field Ornithology 75:89–95. Pettingill, O. S., Jr. 1976. The prey of six species of hawks in northern lower Michigan. Jack-Pine Warbler 54:70–74. Picman, J. 1987. An inexpensive camera setup for the study of egg predation at artificial nests. Journal of Field Ornithology 58:372–382. Picman, J. 1992. Egg destruction by Eastern Meadowlarks. Wilson Bulletin 104:520–525. Picman, J., and J. Belles-Isles. 1988. Interspecific egg pecking by the Black-capped Chickadee. Wilson Bulletin 100:664–665. Picman, J., M. L. Milks, and M. Leptich. 1993. Patterns of predation on passerine nests in marshes: effects of water depth and distance from edge. Auk 110:89–94. Picman, J., and L. M. Schriml. 1994. A camera study of temporal patterns of nest predation in different habitats. Wilson Bulletin 106:456–465. Pierce, A. J., and K. Pobprasert. 2007. A portable system for continuous monitoring of bird nests

206

STUDIES IN AVIAN BIOLOGY

using digital video recorders. Journal of Field Ornithology 78:322–328. Pietz, P. J., and D. A. Granfors. 2000. Identifying predators and fates of grassland passerine nests using miniature video cameras. Journal of Wildlife Management 64:71–87. Pietz, P. J., and D. A. Granfors. 2005. Parental nest defense on videotape: more reality than “myth.” Auk 122:701–705. Pinxten, R., E. De Ridder, M. De Cock, and M. Eens. 2003. Castration does not decrease nonreproductive aggression in yearling male European Starlings (Sturnus vulgaris). Hormones and Behavior 43:394–401. Pithon, J. A., and C. Dytham. 1999. Breeding performance of Ring-necked Parakeets Psittacula krameri in small introduced populations in southeast England. Bird Study 46:342–347. Poole, K. G., and D. A. Boag. 1988. Ecology of Gyrfalcons, Falco rusticolus, in the central Canadian Arctic: diet and feeding behaviour. Canadian Journal of Zoology 66:334–344. Poole, K. G., and R. G. Bromley. 1988. Natural history of the Gyrfalcon in the central Canadian Arctic. Arctic 41:31–38. Porkert, J., and M. Spinka. 2004. Provisioning behaviour at the nest in single-parent versus biparental nests and male versus female parents in the Common Redstart (Phoenicurus phoenicurus). Acta Ethologica 7:29–36. Portnoy, J. W., and W. E. Dodge. 1979. Red-shouldered Hawk nesting ecology and behavior. Wilson Bulletin 91:104–117. Poulin, R. G., and L. D. Todd. 2006. Sex and nest stage differences in the circadian foraging behaviors of nesting Burrowing Owls. Condor 108:856–864. Proudfoot, G. A. 1996. Miniature video-board camera used to inspect natural and artificial nest cavities. Wildlife Society Bulletin 24:528–530. Proudfoot, G. A. 2002. Two optic systems assist removal of nestlings from nest cavities. Wildlife Society Bulletin 30:956–959. Pulliainen, E. 1978. Behaviour of a Willow Grouse Lagopus l. lagopus at the nest. Ornis Fennica 55:141–148. Purcell, K. L., and J. Verner. 1999. Nest predators of open and cavity nesting birds in oak woodlands. Wilson Bulletin 111:251–256. Rader, M. J., T. W. Teinert, L. A. Brennan, F. Hernández, N. J. Silvy, and X. B. Wu. 2007. Identifying predators and nest fates of bobwhites in southern Texas. Journal of Wildlife Management 71:1626–1630. Reif, V., and R. Tornberg. 2006. Using time-lapse digital video recording for a nesting study of birds of prey. European Journal of Wildlife Research 52:251–258. Reillo, P. R., S. Durand, and K. A. McGovern. 1999. First sighting of eggs and chicks of the Red-necked

NO. 43

Ribic, Thompson, and Pietz

Amazon Parrot (Amazona arausiaca) using an intra-cavity video probe. Zoo Biology 18:63–70. Reitsma, L. 1992. Is nest predation density dependent? A test using artificial nests. Canadian Journal of Zoology 70:2498–2500. Reitsma, L. R., R. T. Holmes, and T. W. Sherry. 1990. Effects of removal of red squirrels, Tamiasciurus hudsonicus, and eastern chipmunks, Tamias striatus, on nest predation in a northern hardwood forest: an artificial nest experiment. Oikos 57:375–380. Rejt, L. 2001. Feeding activity and seasonal changes in prey composition of urban Peregrine Falcons Falco peregrinus. Acta Ornithologica 36:165–169. Rejt, L. 2004. Nocturnal feeding of young by urban Peregrine Falcons (Falco peregrinus) in Warsaw (Poland). Polish Journal of Ecology 52:63–68. Rejt, L., K. Turlejski, K. Bronche, and A. M. Topczewski. 2000. Can food caching increase frequency of chicks’ feeding in urban kestrels Falco tinnunculus? Acta Ornithologica 35:217–221. Renfrew, R. B., and C. A. Ribic. 2003. Grassland passerine nest predators near pasture edges identified on videotape. Auk 120:371–383. Richardson, D. M., J. W. Bradford, P. G. Range, and J. Christensen. 1999. A video probe system to inspect Red-cockaded Woodpecker cavities. Wildlife Society Bulletin 27:353–356. Robinson, W. D., G. Rompré, and T. R. Robinson. 2005. Videography of Panama bird nests shows snakes are principal predators. Ornitologia Neotropical 16:187–195. Rogers, A. S., S. DeStefano, and M. F. Ingraldi. 2005. Quantifying Northern Goshawk diets using remote cameras and observations from blinds. Journal of Raptor Research 39:303–309. Royama, T. 1959. A device of an auto-cinematic foodrecorder. Tori 15:20–24. Royama, T. 1970. Factors governing the hunting behaviour and selection of food by the Great Tit (Parus major L.). Journal of Animal Ecology 39:619–668. Rytkönen, S., K. Koivula, and M. Orell. 1996. Patterns of per-brood and per-offspring provisioning efforts in the Willow Tit Parus montanus. Journal of Avian Biology 27:21–30. Sabine, J. B., J. M. Meyers, and S. H. Schweitzer. 2005. A simple, inexpensive video camera setup for the study of avian nest activity. Journal of Field Ornithology 76:293–297. Sabine, J. B., S. H. Schweitzer, and J. M. Meyers. 2006. Nest fate and productivity of American Oystercatchers, Cumberland Island National Seashore, Georgia. Waterbirds 29:308–314. Sanders, M. D., and R. F. Maloney. 2002. Causes of mortality at nests of ground-nesting birds in the Upper Waitaki Basin, South Island, New Zealand: a 5-year video study. Biological Conservation 106: 225–236.

Savidge, J. A., and T. F. Seibert. 1988. An infrared trigger and camera to identifiy predators at artificial nests. Journal of Wildlife Management 52:291–294. Sawin, R. S., M. W. Lutman, G. M. Linz, and W. J. Bleier. 2003. Predators on Red-winged Blackbird nests in eastern North Dakota. Journal of Field Ornithology 74:288–292. Schaefer, T. 2004. Video monitoring of shrub-nests reveals nest predators. Bird Study 51:170–177. Schaefer, T., and G. Heine. 2002. Test of an inexpensive camera set for nest and animal activity observations. Vogelwarte 41:295–298. Schaeff, C., and J. Picman. 1988. Destruction of eggs by Western Meadowlarks. Condor 90:935–937. Schönfeld, F. 2007. Einfluss des Insektizids Dimilin (diflubenzuron) auf die Avifauna eines EichenHainbuchen-Waldes in Unterfranken. Ornithologischer Anzeiger 46:104–120. Sejberg, D., S. Bensch, and D. Hasselquist. 2000. Nestling provisioning in polygynous Great Reed Warblers (Acrocephalus arundinaceus): do males bring larger prey to compensate for fewer nest visits? Behavioral Ecology and Sociobiology 47:213–219. Selås, V., R. Tveiten, and O. M. Aanonsen. 2007. Diet of Common Buzzards (Buteo buteo) in southern Norway determined from prey remains and video recordings. Ornis Fennica 84:97–104. Sharp, B. L., and B. E. Kus. 2004. Sunrise nest attendance and aggression by Least Bell’s Vireos fail to deter cowbird parasitism. Wilson Bulletin 116:17–22. Sharp, B. L., B. L. Peterson, and B. E. Kus. 2005. Puncture-ejection of own egg by Least Bell’s Vireo and potential implications for anti-parasitism defense. Western Birds 36:64–66. Sieving, K. E., and M. F. Willson. 1999. A temporal shift in Steller’s Jay predation on bird eggs. Canadian Journal of Zoology 77:1829–1834. Silva, L. M., and D. B. Croft. 2007. Nest-site selection, diet and parental care of the Wedge-tailed Eagle Aquila audax in western New South Wales. Corella 31:23–31. Skipnes, K. 1983. Incubation behaviour of the Arctic Tern Sterna paradisaea, in relation to time of day and stage of incubation. Ardea 71:211–215. Slagsvold, T., and S. Rohwer. 2000. Behavioral domination of food delivery by Tree Swallow nestlings. Wilson Bulletin 112:278–281. Sloan, S. S., R. T. Holmes, and T. W. Sherry. 1998. Depredation rates and predators at artificial bird nests in an unfragmented northern hardwoods forest. Journal of Wildlife Management 62:529–539. Small, S. L. 2005. Mortality factors and predators of Spotted Towhee nests in the Sacramento Valley, California. Journal of Field Ornithology 76:252–258. Smith, M. L. 2004. Edge effects on nest predators in two forested landscapes. Canadian Journal of Zoology 82:1943–1953.

NEST CAMERA TECHNOLOGY

207

Smithers, B. L., C. W. Boal, and D. E. Andersen. 2005. Northern Goshawk diet in Minnesota: an analysis using video recording systems. Journal of Raptor Research 39:264–273. Sorenson, M. D. 1991. The functional significance of parasitic egg laying and typical nesting in redhead ducks: an analysis of individual behaviour. Animal Behaviour 42:771–796. Sorenson, M. D. 1993. Parasitic egg laying in Canvasbacks: frequency, success, and individual behavior. Auk 110:57–69. Spittler, H. 1995. Ein Beitrag zur Art und Menge der Beute während der Jungenaufzucht beim Sperber (Accipiter nisus nisus L.). Zeitschrift für Jagdwissenschaft 41:188–197. Spray, C. J., H. Q. P. Crick, and A. D. M. Hart. 1987. Effects of aerial applications of fenitrothion on bird populations of a Scottish pine plantation. Journal of Applied Ecology 24:29–47. Stake, M. M. 2001. Predation by a great plains rat snake on an adult female Golden-cheeked Warbler. Wilson Bulletin 113:460–461. Stake, M. M., and P. M. Cavanagh. 2001. Removal of host nestlings and fecal sacs by Brown-headed Cowbirds. Wilson Bulletin 113:456–459. Stake, M. M., and D. A. Cimprich. 2003. Using video to monitor predation at Black-capped Vireo nests. Condor 105:348–357. Stake, M. M., J. Faaborg, and F. R. Thompson III. 2004. Video identification of predators at Goldencheeked Warbler nests. Journal of Field Ornithology 75:337–344. Stake, M. M., F. R. Thompson III, J. Faaborg, and D. E. Burhans. 2005. Patterns of snake predation at songbird nests in Missouri and Texas. Journal of Herpetology 39:215–222. Staller, E. L., W. E. Palmer, J. P. Carroll, R. P. Thornton, and D. C. Sisson. 2005. Identifying predators at Northern Bobwhite nests. Journal of Wildlife Management 69:124–132. Steidl, R. J., C. R. Griffin, and L. J. Niles. 1991. Differential reproductive success of Ospreys in New Jersey. Journal of Wildlife Management 55:266–272. Stevens, D. K., G. Q. A. Anderson, P. V. Grice, K. Norris, and N. Butcher. 2008. Predators of Spotted Flycatcher Muscicapa striata nests in southern England as determined by digital nest-cameras. Bird Study 55:179–187. Storch, S., D. Grémillet, and B. M. Culik. 1999. The telltale heart: A non-invasive method to determine the energy expenditure of incubating Great Cormorants Phalacrocorax carbo carbo. Ardea 87:207–215. Strong, A. M., R. J. Sawicki, and G. T. Bancroft. 1994. Estimating White-crowned Pigeon population size from flight-line counts. Journal of Wildlife Management 58:156–162.

208

STUDIES IN AVIAN BIOLOGY

Sullivan, B. D., and J. J. Dinsmore. 1990. Factors affecting egg predation by American Crows. Journal of Wildlife Management 54:433–437. Summers, R. W. 2006. Patterns of nest attendance by a pair of Parrot Crossbills. British Birds 99:562–568. Sykes, P. W., Jr., W. E. Ryman, C. B. Kepler, and J. W. Hardy. 1995. A 24-hour remote surveillance system for terrestrial wildlife studies. Journal of Field Ornithology 66:199–211. Takeuchi, T., S. Shiraki, M. Nashimoto, R. Matsuki, S. Abe, and H. Yatake. 2006. Regional and temporal variations in prey selected by Golden Eagles Aquila chrysaetos during the nestling period in Japan. Ibis 148:79–87. Tarwater, C. E. 2008. Predators at nests of the Western Slaty Antshrike (Thamnophilus atrinucha). Wilson Journal of Ornithology 120:620–624. Teather, K. L. 1992. An experimental study of competition for food between male and female nestlings of the Red-winged Blackbird. Behavioral Ecology and Sociobiology 31:81–87. Temple, S. A. 1972. A portable time-lapse camera for recording wildlife activity. Journal of Wildlife Management 36:944–947. Teunissen, W., H. Schekkerman, F. Willems, and F. Majoor. 2008. Identifying predators of eggs and chicks of Lapwing Vanellus vanellus and Black-tailed Godwit Limosa limosa in the Netherlands and the importance of predation on wader reproductive output. Ibis 150(Suppl. 1):74–85. Tewksbury, J. J., T. E. Martin, S. J. Hejl, M. J. Kuehn, and J. W. Jenkins. 2002. Parental care of a cowbird host: caught between the costs of egg-removal and nest predation. Proceedings of the Royal Society of London, Series B 269:423–429. Thibault, M., and R. McNeil. 1995. Day- and nighttime parental investment by incubating Wilson’s Plovers in a tropical environment. Canadian Journal of Zoology 73:879–886. Thibault, J., and P. Villard. 2005. Reproductive ecology of the Corsican Nuthatch Sitta whiteheadi. Bird Study 52:282–288. Thompson, F. R., III, and D. E. Burhans. 2003. Predation of songbird nests differs by predator and between field and forest habitats. Journal of Wildlife Management 67:408–416. Thompson, F. R., III, and D. E. Burhans. 2004. Differences in predators of artificial and real songbird nests: evidence of bias in artificial nest studies. Conservation Biology 18:373–380. Thompson, F. R., III, W. Dijak, and D. E. Burhans. 1999. Video identification of predators at songbird nests in old fields. Auk 116:259–264. Thorsen, M., J. Innes, G. Nugent, and K. Prime. 2004. Parental care and growth rates of New Zealand Pigeon (Hemiphaga novaeseelandiae) nestlings. Notornis 51:136–140.

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Tornberg, R., and V. Reif. 2007. Assessing the diet of birds of prey: a comparison of prey items found in nests and images. Ornis Fennica 84:21–31. Tremblay, I., D. Thomas, J. Blondel, P. Perret, and M. M. Lambrechts. 2005. The effect of habitat quality on foraging patterns, provisioning rate and nestling growth in Corsican Blue Tits Parus caeruleus. Ibis 147:17–24. Tripet, F., M. Glaser, and H. Richner. 2002. Behavioural responses to ectoparasites: time-budget adjustments and what matters to Blue Tits Parus caeruleus infested by fleas. Ibis 144:461–469. Underwood, T. J., and S. G. Sealy. 2006. Grasp-ejection in two small ejecters of cowbird eggs: a test of billsize constraints and the evolutionary equilibrium hypothesis. Animal Behaviour 71:409–416. Unger, C., and H. Peter. 2002. Elterliches Investment der Dohle Corvus monedula bei der Jungenaufzucht in der Kolonie Schulpforte (Sachsen-Anhalt). Vogelwelt 123:55–64. van Veen, J. C. 2003. Dietary shifts and brood reduction in video-observed breeding Tawny Owls Strix aluco. Vogelwelt 124:295–308. Vander Haegen, W. M., and R. M. DeGraaf. 1996. Predation on artificial nests in forested riparian buffer strips. Journal of Wildlife Management 60:542–550. Vander Haegen, W. M., M. A. Schroeder, and R. M. DeGraaf. 2002. Predation on real and artificial nests in shrub steppe landscapes fragmented by agriculture. Condor 104:496–506. Vanderwerf, E. A. 2001. Rodent control decreases predation on artificial nests in O‘ahu ‘Elepaio habitat. Journal of Field Ornithology 72:448–457. Villard, P., and J. Thibault. 2001. Données sur les nids, la croissance des poussins et les soins parentaux chez la Sittelle Corse Sitta whiteheadi. Alauda 69:465–474. Warnke, D. K., D. E. Andersen, C. R. Dykstra, M. W. Meyer, and W. H. Karasov. 2002. Provisioning rates and time budgets of adult and nesting Bald Eagles at inland Wisconsin nests. Journal of Raptor Research 36:121–127. Weidinger, K. 2002. Interactive effects of concealment, parental behaviour and predators on the survival of

open passerine nests. Journal of Animal Ecology 71:424–437. Weidinger, K. 2006. Validating the use of temperature data loggers to measure survival of songbird nests. Journal of Field Ornithology 77:357–364. Weldon, A. J., and N. M. Haddad. 2005. The effects of patch shape on Indigo Buntings: evidence for an ecological trap. Ecology 86:1422–1431. Weller, M. W., and D. V. Derksen. 1972. Use of timelapse photography to study nesting activities of birds. Auk 89:196–200. Werner, S. M., S. J. Hejl, and T. Brush. 2007. Breeding ecology of the Altamira Oriole in the lower Rio Grande Valley, Texas. Condor 109:907–919. Whelan, C. J., M. L. Dilger, D. Robson, N. Hallyn, and S. Dilger. 1994. Effects of olfactory cues on artificialnest experiments. Auk 111:945–952. Whitehead, A. L., K. Edge, A. F. Smart, G. S. Hill, and M. J. Willans. 2008. Large scale predator control improves the productivity of a rare New Zealand riverine duck. Biological Conservation 141:2784–2794. Wiehn, J., P. Ilmonen, E. Korpimäki, M. Pahkala, and K. Wiebe. 2000. Hatching asynchrony in the Eurasian Kestrel Falco tinnunculus: an experimental test of the brood reduction hypothesis. Journal of Animal Ecology 69:85–95. Wille, F., and K. Kampp. 1983. Food of the Whitetailed Eagle Haliaeetus albicilla in Greenland. Holarctic Ecology 6:81–88. Williams, G. E., and P. B. Wood. 2002. Are traditional methods of determining nest predators and nest fates reliable? An experiment with Wood Thrushes (Hylocichla mustelina) using miniature video cameras. Auk 119:1126–1132. Williams, T. 1999. Factors affecting chick survival in captive Bali Starlings Leucopsar rothschildi. Dodo 35:93–108. Zárybnická, M., O. Sedlácek, and E. Korpimäki. 2009. Do Tengmalm’s Owls alter parental feeding effort under varying conditions of main prey availability? Journal of Ornithology 150:231–237. Zegers, D. A., S. May, and L. J. Goodrich. 2000. Identification of nest predators at farm/forest edge and forest interior sites. Journal of Field Ornithology 71:207–216.

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INDEX

Accipter cooperii. See Hawk, Cooper’s (Accipter cooperii) adult behavior, cameras used in study of, 189 age. See also nest age; nestling age nest abandonment and adult, 162, 168 nest predation and brood, 12, 13, 16 nest recess and adult, 80, 82 Agelaius phoeniceus. See Blackbird, Red-winged (Agelaius phoeniceus) agricultural grasslands, bird productivity and nest predation in, 119–131 AIC (Akaike’s Information Criterion), 63, 138, 165, 166, 167 Aix sponsa. See Duck Wood (Aix sponsa) Akaike’s information criterion. See AIC (Akaike’s Information Criterion) alfalfa (Medicago sativa), 120 American Ornithologists’ Union Report on Use of Wild Birds in Research, 79 Ammodramus henslowii. See Sparrow, Henslow’s (Ammodramus henslowii) Ammodramus leconteii. See Sparrow, Le Conte’s (Ammodramus leconteii) Ammodramus savannarum. See Sparrow, Grasshopper (Ammodramus savannarum) Ammondramus bairdii. See Sparrow, Baird’s (Ammodramus bairdii) Anas acuta. See Pintail, Northern (Anas acuta) Anas platyrhynchos. See Mallard (Anas platyrhynchos) Andropogon gerardii. See bluestem, big (Andropogon gerardii) Anseriformes, 35, 36 ant, fire (Solenopsis invicta) as nest predator of bobwhites, 39, 163, 166, 169 habitat favored by, 136 partial depredation and, 161 of songbird nests, 135, 139, 140, 141, 143–144, 145 in southern latitudes, 25, 26–27 Anthus pratensis. See Pipit, Meadow (Anthus pratensis) Anthus spinoletta. See Pipit, Water (Anthus spinoletta)

Antus spragueii. See Pipit, Sprague’s (Antus spragueii) Aphelocoma californica. See Scrub-Jay, Western (Aphelocoma californica) Arborophila chloropus. See Partridge, Scaly-breasted (Arborophila chloropus) ArcMap 9.2, 138 ArcView GIS, 123 Arenaria interpres. See Turnstone, Ruddy (Arenaria interpres) Aristida stricta. See wiregrass (Aristida stricta) armadillos, nine-banded (Dasypus novemcinctus), as bobwhite nest predator, 163 artificial nest studies, xiv, 36 aspen, quaking (Populus tremuloides), 107 Audubon, John James, 58 autocinematic food-recorder, 185 auxiliary markers, predator identification and, 18–19 avian ecology, xiii–xiv Aythya americana. See Redhead (Aythya americana) Aythya valisineria. See Canvasback (Aythya valisineria) back sleep, 105, 106, 108, 110 badger, American (Taxidea taxus) activity, 129 as nest predator, 9, 10, 124, 127, 128, 129 Baeolophus spp. See Titmouse (Baeolophus spp.) barberry, Japanese (Berberis thunbergii), 107 Bartramia longicauda. See Sandpiper, Upland (Bartramia longicauda) Bassariscus astutus. See Ringtail (Bassariscus astutus) batteries, for video surveillance systems, 187, 188, 194 bear, brown (Ursus arctos middenorffi), as nest predator, 38 bee balm (Monarda spp.), 107 beetles (Coleoptera), as nest predators, 64 begging behavior of nestlings, 17 Bent of the River Audubon Center, 106–107 Berberis thunbergii. See barberry, Japanese (Berberis thunbergii) Biblioline Wildlife and Ecology Studies Worldwide, 186

211

biparental incubation, 90 diel patterns for, 89, 96 monitoring, 91–92 recesses, 94, 96, 98, 100 restlessness and, 97 uniparental incubation vs., 93–94 biparental species, nest defense and, 101 bird conservation, xiii–xiv. See also passerine conservation control of predators and, 28–30 habitat and, 23 landscape approach to, 120–121 predator identification and, 23–24 Bird Conservation Area model, 29–30 bird productivity, in agricultural grasslands, 119–131 birds, as nest predators, 11. See also individual predators Birds of North America, 55, 109 blackberry/wineberry/dewberry (Rubus spp.), 107 Blackbird, Red-winged (Agelaius phoeniceus) hatching time, 51 nest defense and, 150 nest fate and, 6 Blackbird, Yellow-headed (Xanthocephalus xanthocephalus), incubation attentiveness and, 71 black-eyed susan (Rudbeckia hirta), 107 bluegrass, Kentucky (Poa pratensis), 24, 121, 122, 150 bluestem, big (Andropogon gerardii), 25, 107, 121, 150 bluestem, little (Schizchyrium scoparium), 25, 107, 121, 150 bobcat (Lynx rufus), as bobwhite nest predator, 163 Bobolink (Dolichonyx oryzivorus) fledging age for, 47 hatching and fledging times for, 50, 51, 52, 53, 54–56, 57–58 nest fate and, 6 nest defense by, 16, 149, 155–156 nesting habitat of, 119, 125, 130 nesting period, 123 nest success of, 125 nocturnal activity of nesting, 107–114 as part of North Dakota and Wisconsin grassland bird communities, 24 response to neck ligatures on nestlings, 15 Bobwhite, Northern (Colinus virginianus) camera studies of, 37 incubation behavior patterns in, 77–85 nest defenses by, 36–37, 163, 169 nest predation of, 36, 39, 40 nest recess length among, 79–85 partial nest depredation of, 5, 161–169 body size, waking time and, 113 Bonasa umbellus. See Grouse, Ruffed (Bonasa umbellus) Bos taurus. See cattle (Bos taurus) Bouteloua curtipendula. See grama, side-oats (Bouteloua curtipendula) Branta canadensis occidentalis. See Goose, Dusky Canada (Branta canadensis occidentalis) breeding attempts, nest attendance and number of, 85 brome (Bromus spp.), 150 brome, smooth (Bromus inermis), 25, 121, 122, 150 brood age, nest predation and, 12, 13, 16 Bucephala clangula. See Goldeneye, Common (Bucephala clangula)

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bullet camera, 41 bullsnake (Pituophis catenifer), as nest predator, 11, 63–64 Bunting, Indigo (Passerina cyanea), 191 nocturnal activity of nesting, 105, 106, 107–114 as part of Missouri and Georgia forest bird communities, 25 Bunting, Painted (Passerina ciris), nest survival of, 140 Buteo jamaicensis. See Hawk, Red-tailed (Buteo jamaicensis) Buteo platypterus. See Hawk, Broad-winged (Buteo platypterus) cables, for video surveillance systems, 194–195 Calcarius ornatus. See Longspur, Chestnut-collared (Calcarius ornatus) Calidris alpina. See Dunlin (Calidris alpina) Calidris fuscicollis. See Sandpiper, White-rumped (Calidris fuscicollis) Calidris pusilla. See Sandpiper, Semipalmated (Calidris pusilla) camcorders, 191–192 cameras. See also video surveillance systems color, 194 digital noise reduction, 194 focal length of lenses, 193–194 minature, 196 nest abandonment and presence of, 5 still-frame, 191–192 technological improvements needed in, 41 trail, 191–192 for use with DVRs, 193–194 wide-dynamic range, 194 Canadian Arctic, incubation behavior of shorebirds in, 90–101 canids, effects of cameras and human activity on, 40 Canis latrans. See coyote (Canis latrans) Canis lupus familiaris. See dog (Canis lupus familiaris) canopy nests, predation risk and, 139, 140, 141, 142, 145 Canvasback (Aythya valisineria) camera studies of, 37 as nest predator, 40 parasitic egg-laying and, 38 Cardinal, Northern (Cardinalis cardinalis) nest survival of, 140 as part of a Georgia forest bird community, 25 Carduus. See thistle (Cirsium and Carduus spp.) Carya spp. See hickory (Carya spp.) cat (Felis catus), as nest predator, 10, 127, 128 cattle (Bos taurus), as nest predator, 8, 10, 127 Centrocercus urophasianus. See Sage-Grouse, Greater (Centrocercus urophasianus) Cervis canadensis. See elk, American (Cervis canadensis) Charadriiformes, 36, 39 Charadrius semipalmatus. See Plover, Semipalmated (Charadrius semipalmatus) Charadrius vociferous. See Killdeer (Charadrius vociferous) chemical cues, used by predators to locate nests, 137, 143, 157 Chen caerulescens. See Goose, Lesser Snow (Chen caerulescens) Chen rossii. See Goose, Ross’s (Chen rossii)

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cherry, black (Prunus serotina), 107 Chickadee (Poecile spp.), nest defense and, 150 Circus cyaneus. See Harrier, Northern (Circus cyaneus) Cirsium. See thistle (Cirsium and Carduus spp.) clutch size length of hatching period and, 47, 50, 52 nest abandonment and, 162, 166, 167, 168, 169 nest recess and, 80, 82, 83 coachwhip, western (Coluber flagellum testaceus), as nest predator, 139 Coats Island (Canada), shorebird incubation behavior at, 90–101 Cole, Leon J., 47–48 Coleoptera. See beetles (Coleoptera) Colinus virginianus. See Bobwhite, Northern (Colinus virginianus) color cameras, 194 Coluber constrictor. See racer, North American (Coluber constrictor) Coluber flagellum testaceus. See coachwhip, Western (Coluber flagellum testaceus) Coluber spp. See racer (Coluber spp.) Colubrinae, as nest predator, 157 Connecticut, nocturnal activity of shrubland passerines in, 106–114 connectors, for video surveillance systems, 194–195 conservation. See bird conservation; passerine conservation Conservation Reserve Program fields bird productivity and nest predation in, 119, 121–131 habitat establishment and, 120 nest predators in, 122 nocturnal activities at passerine nests in, 107 patterns of passerine nest predators in, 24–25, 28, 30 study of nest defense among passerines in, 150 cool-season grasses, 24–25 Cornus racemosa. See dogwood, gray (Cornus racemosa) corn (Zea mays), 8, 121, 150 corvids, effects of cameras and human activity on, 40 Corvus brachyrhynchos. See Crow, American (Corvus brachyrhynchos) Corvus corax. See Raven, Common (Corvus corax) Corvus moneduloides. See Crows, New Caledonian (Corvus moneduloides) cow (Bos taurus), as nest predator, 8, 10, 128 Cowbird, Brown-headed (Molothrus ater) egg and nestling fates, 7 egg hatching time of, 50, 58 fledging time, 52, 53, 56 nest defense against, 15, 16 video surveillance systems and, 65 Cowbird, Brown-headed (Molothrus ater) parasitism Black-capped Vireo and Golden-cheeked Warbler nests and, 136 Blue-winged Warbler nest and, 111 hatching time of hosts and, 48, 49, 50, 51 fledging age of hosts and, 48, 49, 52, nest abandonment and, 5, 6 Sprague’s Pipit nests and, 175 Cowbird, Brown-headed (Molothrus ater) predation direct control of, 28

habitat and, 135 landscape factors in, 145 of passerine nests, 6, 7, 9, 11, 14, 25, 26, 27, 120, 128, 139 shrub nests and, 141 coyote (Canis latrans) activity, 129 as bobwhite nest predator, 163 as grassland passerine nest predator, 5, 9, 10,124, 128, 129 as Sprague’s Pipit nest predator, 173, 176, 179 Crow, American (Corvus brachyrhynchos) nest defense and, 150 as nest predator, 139 Crow, New Caledonian (Corvus moneduloides), 196 Cygnus buccinator. See Swan, Trumpeter (Cygnus buccinator) daily nest survival, 12, 14, 16, 17, 48, 57, 61, 63, 64, 119, 125, 127, 130, 175, 176, 178 Dasypus novemcinctus. See armadillos, nine-banded (Dasypus novemcinctus) data analysis, new possibilities with digital video imagery, 42 data storage, improvements needed in video surveillance, 42 data transmission, improvements needed in video surveillance, 41–42 day of year, nest predation and, 143 deer, as Sprague’s Pipit nest predator, 173, 176, 179 deer, white-tailed (Odocoileus virginianus) activity, 128-129 as nest predator, 7, 8, 9, 10, 39, 124, 128–129, 165 departure from nest nest predation and adult, 176, 177, 178 time in morning, 111, 112 Dickcissel (Spiza americana), fledgling survival of, 53 Didelphis marsupialis. See opossum (Didelphis marsupialis) Didelphis virginiana. See opossum, Virginia (Didelphis virginiana) diel patterns in incubation, 89, 92–93, 94, 96 digital camera technology, 189 digital noise reduction cameras, 194 digital recorders, 192–193 digital video recording system, user-built, 186–188, 195–196 schematic, 187 direct control of nest predators, 28-29 diurnal nest predators, 4, 8–9, 12, 13 dog (Canis lupus familiaris), as nest predator, 10, 128 dogwood, gray (Cornus racemosa), 107 Dolichonyx oryzivorus. See Bobolink (Dolichonyx oryzivorus) Driftless Area, 121 Duck, Wood (Aix sponsa), egg parasitism and, 38–39 Dunlin (Calidris alpina), incubation behavior of, 91, 93, 94, 95, 96, 97, 98, 101 DVRs, 187, 188, 192–193 cameras for use with, 193–194 East Bay (Canada), shorebird incubation behavior at, 90–101 ecological time, 150

INDEX

213

edges nesting success and, 130–131 nest predation and, 29, 30, 119, 120, 127–128 nest survival and, 126–127 Sprague’s Pipit nest predators and, 180 egg neglect among shorebirds, 92, 99, 100–101 defined, 89 eggs fate of grassland passerine, 7 nest predation and age of, 176, 177 Elaphe obsoleta. See ratsnake, Texas (Pantherophis obsoletus) Eleagnus umbellata. See olive, autumn (Eleagnus umbellata) elk, American (Cervis canadensis), as nest predator, 39 Empidonax traillii extimus. See Flycatcher, Southwestern Willow (Empidonax traillii extimus) Empidonax virescens. See Flycatcher, Acadian (Empidonax virescens) ermine (Mustela erminea), as nest predator, 9, 10 Falco sparverius. See Kestrel, American (Falco sparverius) feeding ecology, 189 feeding time, first, 111, 112 Felis catus. See cat (Felis catus) final predation, 13 final predation rate, 14 final return time to nest, 109, 110 Fireback, Siamese (Lophura diardii), camera studies of, 37 flagging, 163 fledging forced, 7–8, 53, 56 premature, 5, 7–8, 47–48, 53, 57 synchronous, 58 fledging age estimating, 47–48, 49 from grassland passerine nests, 47–58 video nest surveillance and verification of, 14–15 Florida incubation patterns in Northern Bobwhite nests in, 78–85 partial depredation on Northern Bobwhite nests in, 163–169 Flycatcher, Acadian (Empidonax virescens) as part of a Missouri shrubland and forest bird community, 25 nest predation of, 191 Flycatcher, Southwestern Willow (Empidonax traillii extimus), 28 forbs, 150 forced fledging, 7–8, 53, 56 Fort Hood Military Reservation, 135, 137 fox (Vulpes spp.), as nest predator, 5, 10, 128. See also fox, gray (Urocyon cinereoargenteus); fox, red (Vulpes vulpes) fox, gray (Urocyon cinereoargenteus), as nest predator, 139, 163 fox, red (Vulpes vulpes), as nest predator, 9, 10, 14, 28, 163, 179 foxsnake, western (Mintonius vulpinus), as nest predator, 11, 27, 128, 153–157

214

STUDIES IN AVIAN BIOLOGY

fragmentation, xiv, 29, 30 front sleep, 106, 108 fuel cells, 194 Galliformes incubation behavior of, 77–78, 85 video surveillance of, 35, 36 Gallinago delicata. See Snipe, Wilson’s (Gallinago delicata) gamebirds nest predation and, 36 video surveillance of, 35–43 gartersnake (Thamnophis spp.) chemical cues used by, 157 as nest predator of grassland passerines, 8, 9, 11, 27 as nest predator of Sprague’s Pipit, 173, 176, 178, 179, 180 gartersnake, common (Thamnophis sirtalis), as nest predator, 11, 127, 128, 153–157 gartersnake, Plains (Thamnophis radix) nest defense against, 158 as nest predator, 5, 9 geographic patterns of nest predation, 26–27 Georgia incubation patterns in Northern Bobwhite in, 78–85 partial depredation on Northern Bobwhite nests in, 163–169 passerine nest predation in, 24–27 Geothlypis trichas. See Yellowthroat, Common (Geothlypis trichas) Global Positioning System, locations of nests using, 122 Glycine max. See soybeans (Glycine max) Gnatcatcher, Blue-gray (Polioptila caerulea), nest survival of, 140 Goldeneye, Common (Bucephala clangula) camera studies of, 37 nest parasitism and, 38 Golden-Plover, American (Pluvialis dominica), incubation behavior of, 91, 93, 95, 96, 97 goldenrod (Solidago spp.), 107 Goose, Dusky Canada (Branta canadensis occidentalis), 40 nest predation of, 38 Goose, Lesser Snow (Chen caerulescens), 78 Goose, Ross’s (Chen rossii), 78 gopher, northern pocket (Thomomys talpoides), Sprague’s Pipit nest and, 175 grama, side-oats (Bouteloua curtipendula), 107, 121, 150 grass, Indian (Sorghastrum nutans), 25, 107, 121, 150 grass, needle (porcupine) (Heterostipa spartea), 25, 121 grass, needle (porcupine) (Stipa spartea), 107, 150 grass, panic (Panicum spp.), 107, 121, 150 grassland birds declining populations of, 120 nest defense against snakes, 149–158 productivity and nest predation of, 119–131 video camera technology and study of, xiv–xv grassland passerines declining populations of, 3–4 hatching and fledging age, 47–58 nest predation among, 3–4, 5–8 nocturnal activity of nesting, 105–114 parental and nestling behaviors, 17–18 predator identification and ecology, 8–12

NO. 43

Ribic, Thompson, and Pietz

predator-prey behavior, 15–17 video-monitoring nests, 3–19 grassland songbirds, predation rates for, 173 grass species. See also individual species cool-season, 24–25 warm-season, 25 Grosbeak, Blue (Guiraca caerulea), as part of a Georgia forest bird community, 25 ground squirrel, Franklin’s (Poliocitellus franklinii), as nest predator, 9, 10 ground squirrels nest defense against, 15 as nest predators, 27, 39 ground squirrel, Richardson’s (Urocitellus richardsonii), as nest predator, 178 ground squirrel, thirteen-lined (Ictidomys tridecemlineatus) activity, 119, 129, 130 as grassland passerine nest predator, 9, 15, 29–30, 119, 120, 124, 127–128, 129, 130 habitat of, 27 nest defense against, 16, 158, 180 predation on adult Chestnut-collared Longspur, 15 as Sprague’s Pipit nest predator, 173, 174, 176, 179, 180–181 as Western Meadowlark nest predator, 64 Grouse, Ruffed (Bonasa umbellus), nest predation of, 37 Gudmundsen Sandhills Laboratory, 61, 62 Guiraca caerulea. See Grosbeak, Blue (Guiraca caerulea) habitat. See also edges; specific crops, grasses, trees declining grassland bird populations and loss of, 120 grassland bird, 121 grassland passerine, 107 for predators of grassland passerine nests, 8 nesting survival and, 130 nest predation and, 27, 30 Northern Bobwhite, 78–79, 163 shrubland passerine, 107 Sprague’s Pipit predator, 180–181 Harrier, Northern (Circus cyaneus), as predator of Sprague’s Pipit nests, 9, 11, 14, 173, 174, 176, 178, 179, 180–181 hatching times, from grassland passerine nests, 47–58 Hawk, Broad-winged (Buteo platypterus), as nest predator, 139, 144–145, 191 Hawk, Buteo, as nest predator, 9, 11, 14, 128 Hawk, Cooper’s (Accipter cooperii), as nest predator, 139, 144–145 Hawk, Red-tailed (Buteo jamaicensis), as nest predator, 11 Helmitheros vermivorus. See Warbler, Worm-eating (Helmitheros vermivorus) Heterostipa spartea. See grass, needle (porcupine) (Heterostipa spartea) hickory (Carya spp.), 25 hormones, nest recess and attendance and, 84 Hosmer-Lemeshow goodness-of-fit test, 165, 166 humans forced/premature fledging and human observers, 7–8

impact of at nests, 14, 15 impact on nestling behavior, 15, 17 Hylocichla mustelina. See Thrush, Wood (Hylocichla mustelina) Ictidomys tridecemlineatus. See ground squirrel, thirteenlined (Ictidomys tridecemlineatus) Ictinia mississippiensis. See Kite, Mississippi (Ictinia mississippiensis) illumination, for video surveillance systems, 4, 41, 188, 193, 194 image-recording units, 191–193 incubation influence of weather on shorebird, 89–101 nest attendance and, 63 incubation behavior diel patterns in, 89, 92–93, 94 energetic costs of, 78 monitoring, 91–92 of Northern Bobwhites, 77–85 of Sprague’s Pipit, 67–74 of Sprague’s Pipit and other passerines, 71–73 temporal and weather-related effects on, 94–99, 100 variation within and among days, 100 incubation stage nest abandonment and, 5, 162, 166, 167, 168 nest predation risk during, 12 nest recess and, 80–83, 84 nest survival during, 17, 126 parental behavior during, 17 partial predation and, 166 Sprague’s Pipit nest predation and, 176, 177 indirect control of nest predators, 28 initial predation, 9, 14 initial-predation rates, 12, 13, 14, 16 Iowa bird productivity and nest predation in, 121–131 nest predators of grassland passerines in, 10–11 IR LEDs, 4, 193–194 IR triggers, 192 J. Clark Salyer National Wildlife Refuge, 9, 49, 55, 57 juniper (Juniperus), 142 juniper, Ashe (Juniperus ashei), 25, 27, 136 Juniperus virginiana. See redcedar, Eastern (Juniperus virginiana) Kestrel, American (Falco sparverius), as nest predator, 9, 11 Killdeer (Charadrius vociferous), nest defense and, 149–150 kingsnakes (Lampropeltis getula) as bobwhite nest predator, 163, 165 partial depredation caused by, 161 kingsnake, prairie (Lampropeltis calligaster calligaster), as nest predator, 29 Kite, Mississippi (Ictinia mississippiensis) nests, video surveillance of, 188, 190 Kruskal Wallis test, 108 Lampropeltis calligaster calligaster. See kingsnake, prairie (Lampropeltis calligaster calligaster) Lampropeltis getula. See kingsnakes (Lampropeltis getula)

INDEX

215

Lampropeltis spp., as nest predators, 157 Lampropeltis triangulum. See milksnake (Lampropeltis triangulum) landscape approach to bird management, 120–121 landscape ecology, xiv landscape factors, nest predation and, 136, 138, 139, 143, 144–146 LCD viewing monitors, 193, 195 learned responses, to predation pressure, 150 learning, defensive behaviors and, 157–158 LED technology, 41 lethal predator removal, 28 lighting, for video surveillance systems, 41, 188, 193, 194 likelihood ratio test, 140 logistic exposure method, 17, 123, 175 Longspur, Chestnut-collared (Calcarius ornatus) hatching and fledging times for, 50, 51, 52, 53, 54, 55 nest defense and, 15-16 nest fate and, 6, as part of a North Dakota grassland bird community, 24 Lophura diardii. See Fireback, Siamese (Lophura diardii) Lynx rufus. See bobcat (Lynx rufus) Magpie, Black-billed (Pica hudsonia), as Sprague’s Pipit nest predator, 173, 176 male parental care, Sprague’s Pipits, 73 Mallard (Anas platyrhynchos) camera studies of, 37 nest abandonment following partial depredation and, 169 nocturnal activity of nesting, 106, 113 mammals as dominant nest predators in northern grasslands, 26 nest defense against, 15, 158 as nest predators, 130, 135, 146 as nest predators of grassland passerines, 8, 10–11 as nest predators of Sprague’s Pipit, 175–176 sign left at nests depredated by, 14 Manomet Bird Observatory, xiii MARK software, 63 Meadowlark, Eastern (Sturnella magna) decision model for incubating/brooding birds, 151 fledging survival of, 53, 57 nest defense against snakes by, 149, 153–156 nesting habitat, 119, 125, 130 nesting period, 123 as nest predator, 11 nesting stage and nest survival of, 119 nest survival of, 125–126 nocturnal activity of nesting, 105, 107–114 as part of a Wisconsin grassland bird community, 24 Meadowlark, Western (Sturnella neglecta) attendance patterns and nest survival of, 61–65 hatching time, 50, 51, 52 nest fate and, 6 as nest predator, 11, 64 nesting habitat of, 125 nocturnal activity of, 106 as Sprague’s Pipit nest predator, 173, 176, 178, 179, 180

216

STUDIES IN AVIAN BIOLOGY

Medicago sativa. See alfalfa (Medicago sativa) Megascops asio. See Screech-Owl, Eastern (Megascops asio) Meleagris gallopava. See Turkey, Wild (Meleagris gallopava) Melospiza melodia. See Sparrow, Song (Melospiza melodia) Mephitis mephitis. See skunk, striped (Mephitis mephitis) mesopredators, 27–28 Microtus spp. See voles (Microtus spp.) migratory bird population decline, xiii–xiv milksnake (Lampropeltis triangulum), as nest predator, 11, 127, 153–157 Mimus polyglottos. See Mockingbird, Northern (Mimus polyglottos) miniature cameras, attached to New Caledonian Crows, 196 minimum AIC nest vegetation model, 124, 125–126, 165 mink (Mustela lutreola), 150 mink, American (Neovison vison), as nest predator, 10 Minnesota hatching and fledging times in passerine nests in, 49–58 nest predation of grassland passerines in, 5–17, 24-27 Mintonius vulpinus. See foxsnake, Western (Mintonius vulpinus) Missouri, passerine nest predation in, 25–27 mixed model analysis, for recess length, 82 Mockingbird, Northern (Mimus polyglottos), nest defense and, 150 Molothrus ater. See Cowbird, Brown-headed (Molothrus ater) Monarda spp. See bee balm (Monarda spp.) Montana nest predators of grassland passerines in, 10–11 Sprague’s Pipit nest predators identified in, 174–175, 178–181 Mouse (Peromyscus spp.) nest defense against, 15 as nest predator, 9, 10, 139 as Sprague’s Pipit nest predator, 173, 176, 178, 179 mouse, deer (Peromyscus spp.), as nest predator, 9, 10 mouse, jumping (Zapus spp.), as nest predator, 8, 9, 10 mouse, white-footed (Peromyscus spp.), as nest predator, 10 multiple sensors, for video surveillance, 42 Mustela erminea. See ermine (Mustela erminea) Mustela frenata. See weasel, long-tailed (Mustela frenata) Mustela lutreola. See mink (Mustela lutreola) Mustela nivalis. See weasel, least (Mustela nivalis) Mustela spp. See weasel (Mustela spp.) Nebraska attendance patterns and survival of Western Meadowlark nests in, 61–65 nest predators of grassland passerines in, 10–11 Neotoma spp. See rats, wood (Neotoma spp.) Neovison vison. See mink, American (Neovison vison) nest abandonment among grassland passerines, 5, 6, 7 assessing risk of, 74 following partial depredation, 5, 162, 164–169 nest predation and, 140 video nest surveillance and, 18

NO. 43

Ribic, Thompson, and Pietz

nest age nest predation risk and, 143 pipit nest survival and, 176, 177, 179–180 nest attendance of Western Meadowlark, 61–65 nest predation risk and, 61–62 video surveillance of, 38 nest checks, assessing cause of nest failure using, 12–14 nest defense biparental species and, 101 by bobwhites, 36–37, 163 damage to eggs during, 39 by grassland passerines, 15–16 against snakes, 149, 153–158 nest failure, causes of, 5, 6, 12–14, 135–136 nest fate, standard method of determining, 12–14 nest height, nest predation and, 14, 136 nesting cover, mitigating nest predation by increasing, 28 nesting guild, 138, 139 nesting season, nest recess and point in, 80, 81, 82, 83, 84–85 nestling activity, adult sleep interruption and, 111, 113 nestling age nest attendance and, 63 nest predation and, 16–17, 176, 177 nest recess and, 80, 82 nest survival and, 17 nestling behavior cameras used in study of, 17–18, 186, 189 predation risk and, 17 in response to severe weather, 17–18 nestlings, fate of grassland passerine, 7 nest location cues used by predators for, 137, 143, 157 cues used by snakes for, 143, 157 of grassland passerine nests, 151–152 in grasslands, 121–122 shorebird, 91 Sprague’s Pipit, 68–69, 73–74 using rope-drag method to determine, 62, 65, 69, 91, 121–122, 151–152, 174 using telemetry homing techniques to determine, 79 nest parasitism, 38–39. See also Cowbird, Brown–headed (Molothrus ater) parasitism nest predation activity at nests and increase in, 12 in agricultural grasslands, 119–131 among grassland passerines, 3–4, 5–8, 6, 7 brood age and, 12, 13, 16 categorization of events, 138 daily incubation patterns and, 72–73 defined, 153 diurnal, 8–9, 12, 13 edge effects and, 29, 30, 127–128 gamebird, 36 geographic patterns of, 26–27 habitat and, 27 incubation behavior and, 101 landscape factors and, 136, 138, 139, 143, 144–146 mesopredators and waterfowl, 27–28 nest attendance and, 61–62

nest height and, 14, 136 nestling age and, 16–17 nocturnal, 8–9, 12, 13 predator identity and patterns of, 135–146 rates of for grassland songbirds, 173 time of, 8–9, 12 vegetation and patch variables, 123 nest predation risk daily survival rate and, 14 day of year and nest age and, 143 nestling behavior and, 17 sleep and, 106, 114 urbanization and, 141 nest predator identification bird conservation and, 23–24 cameras used for, xiv, 8–12, 64–65, 131, 137, 173–181, 185, 186, 189 grassland passerines and, 8–12 nest predation patterns and, 135–146 of Sprague’s Pipit, 173–181 video nest surveillance and, 8–12, 18–19, 64–65, 131, 137, 173–181 nest predators activity of, 124 in Conservation Reserve Program fields and remnant prairie, 122 direct control of, 28–29 effect of video nest surveillance on behavior of, 18, 40 of grassland birds, 3–19, 127–128 indirect control of, 28 in pastures, 122 sand track stations and, 122–123 variety of, 8, 16–17, 18 nest recesses ambient temperature and, 83–84 among shorebirds, 94, 95, 96, 98, 100 length of among Northern Bobwhite, 79–85 nests, using cameras to monitor, 185–196 nest searches Sprague’s Pipit, 68 waterfowl, 74 nest success, defined, 49–50, 151 nest survival, 123–124 nestling age and, 17 presence of video nest surveillance and, 18 temporal factors and, 136–137, 138, 141, 143, 146 nest visits fledging age determined from, 57 for monitoring hatching and fledging times, 49–50 by predators, 137 Nice, Margaret Morse, 58 nocturnal activity of nesting shrubland and grassland passerines, 105–114 adult absences during the night, 113–114 final return time to nest, 109, 110 first feeding time, 111, 112 nestling movement and, 111, 113 predation risk and, 106, 114 sleep postures, 109, 110 study areas, 106–107 video surveillance system, 107

INDEX

217

nocturnal activity of nesting shrubland and grassland passerines (continued) waking time, 111, 112, 113 weather and, 109, 113 nocturnal nest predation/predators, 8–9, 12, 13, 106, 114 North Dakota hatching and fledging times in passerine nests in, 49–58 nest predation among grassland passerines in, 5–17, 24–27 oak (Quercus spp.), 25, 136, 142 Odocoileus virginianus. See deer, white-tailed (Odocoileus virginianus) olive, autumn (Eleagnus umbellata), 107 Oporornis formosus. See Warbler, Kentucky (Oporornis formosus) opossum (Didelphis marsupialis), as bobwhite nest predator, 163 opossum, Virginia (Didelphis virginiana), as nest predator, 10, 128, 165 Ovenbird (Seiurus aurocapillus), as part of a Missouri shrubland and forest bird community, 25 Pantherophis alleghaniensis. See ratsnake, Eastern (Pantherophis alleghaniensis) Pantherophis emoryi. See ratsnake, Great Plains (Pantherophis emoryi) Pantherophis guttatus guttatus. See snake, corn (Pantherophis guttatus guttatus) Pantherophis obsoletus. See ratsnake, Texas (Pantherophis obsoletus) Pantherophis spp. See ratsnake (Pantherophis spp.) parental behavior in response to severe weather, 17–18 use of cameras to study, 17–18, 186 parental investment defined, 78, 162 partial depredation and, 162, 165–169 partial predation of Northern Bobwhite nests, 161–169 parental investment and, 162, 165–169 in passerine nests, 5, 14, 15, 16, 25 by snakes, 157 of Sprague’s Pipit nests, 180 Partridge, Scaly-breasted (Arborophila chloropus), camera studies of, 37 Parus major. See Tits, Great (Parus major) Parus palustris. See Tits, Marsh (Parus palustris) Passerculus sandwichensis. See Sparrow, Savannah (Passerculus sandwichensis) Passerina ciris. See Bunting, Painted (Passerina ciris) Passerina cyanea. See Bunting, Indigo (Passerina cyanea) passerine conservation control of predators and, 28–30 predator identification and, 23–24 passerine nest predators. See also nest predators of grassland passerines direct control of, 28–29, 30 indirect control of, 29 patterns of, in midwestern and southern U.S., 24–27 thirteen-lined ground squirrels, 29–30

218

STUDIES IN AVIAN BIOLOGY

passerines. See also grassland passerines; shrubland passerines incubation attentiveness among, 71–74 nest defenses among, 149–158 pastures bird productivity and nest predation in, 121–131 conservation plan for grassland birds and, 120 nest defense by passerines in, 150 Pebble Hill Plantation, 78, 79, 163 peeks, nocturnal behavior and, 105, 106, 113 Peromyscus spp. See mouse, deer (Peromyscus spp.); mouse (Peromyscus spp.); mouse, white-footed (Peromyscus spp.) Phalarope, Red (Phalaropus fulicarius) egg neglect among, 99 incubation behavior, 91, 93, 94–97, 98, 101 Pheasant, Ring-necked of (Phasianus colchicus), nest attendance of, 85 Pica hudsonia. See Magpie, Black-billed (Pica hudsonia) pine, loblolly (Pinus taeda), 25, 78, 163 pine, longleaf (Pinus palustris), 25, 78, 163 pine, shortleaf (Pinus echinata), 78, 163 pine, slash (Pinus elliottii), 25 Pinebloom Plantation, 78, 79 Pintail, Northern (Anas acuta), camera studies of, 37 Pinus echinata. See pine, shortleaf (Pinus echinata) Pinus elliottii. See pine, slash (Pinus elliottii) Pinus palustris. See pine, longleaf (Pinus palustris) Pinus taeda. See pine, loblolly (Pinus taeda) Pipilo erythrphthalmus. See Towhee, Eastern (Pipilo erythrphthalmus) Pipit, Meadow (Anthus pratensis) fledging age and, 57 incubation attentiveness and, 71 Pipit, Sprague’s (Antus spragueii) identification of nest predators, 173–181 incubation behavior of, 67–74 nest defense by, 180 parental behavior and, 17 response to radio-marked nestlings, 15 Pipit, Water (Anthus spinoletta), incubation pattern of, 73 Pituophis catenifer. See bullsnake (Pituophis catenifer) Plover, Black-bellied (Pluvialis squatarola), incubation behavior of, 91, 93, 95, 96, 97, 101 Plover, Semipalmated (Charadrius semipalmatus), incubation behavior of, 91, 93, 94, 95, 96, 97, 101 Pluvialis dominica. See Golden-Plover, American (Pluvialis dominica) Poa pratensis. See bluegrass, Kentucky (Poa pratensis) Poecile spp. See Chickadee (Poecile spp.) Poliocitellus franklinii. See ground squirrel, Franklin’s (Poliocitellus franklinii) Polioptila caerulea. See Gnatcatcher, Blue-gray (Polioptila caerulea) Pooecetes gramineus. See Sparrow, Vesper (Pooecetes gramineus) Populus tremuloides. See aspen, quaking (Populus tremuloides) Prairie-Chicken, Greater (Tympanuchus cupido), 39 Prairie-Chicken, Lesser (Tympanuchus pallidicinctus), 39

NO. 43

Ribic, Thompson, and Pietz

rope-dragging method, 62, 65, 69, 91, 121–122, 151–152, 174 rose, multiflora (Rosa multiflora), 107 Rubus spp. See blackberry/wineberry/dewberry (Rubus spp.) Rudbeckia hirta. See black-eyed susan (Rudbeckia hirta)

predation. See under nest predation predator communities of grassland passerine nests, 8–12, 18 spatial variation in, 8, 18 temporal variation in, 8, 18 predator control, 40 predator dilution, 28 predator exclusion, 28 predator-prey behavior, 15–17 predators. See under nest predator premature fledging, 5, 7–8, 47–48 Procyon lotor. See raccoon (Procyon lotor) prolactin, 84 Prunus serotina. See cherry, black (Prunus serotina) Quercus spp. See oak (Quercus spp.) raccoon (Procyon lotor) activity, 119, 128–129 effects of cameras and human activity on, 40 nest defense against, 15, 158 as nest predator, 8, 9, 10, 27, 28, 119, 120, 124, 127, 128–129, 130, 131, 163 racer (Coluber spp.), as nest predators, 11, 29 racer, North American (Coluber constrictor), as nest predator, 11 raptor. See Hawks, Buteo rat, Hispid cotton (Sigmodon hispidus), as nest predator, 39, 165 rat, wood (Neotoma spp.), damage to video systems and, 195 ratsnake (Pantherophis spp.) as nest predator, 27, 29, 143, 163, 165 partial depredation caused by, 161 ratsnake, black (Elaphe obsoleta). See ratsnake, Texas (Pantherophis obsoletus) ratsnake, Eastern (Pantherophis alleghaniensis), as nest predator, 143 ratsnake, Great Plains (Pantherophis emoryi), as nest predator, 139 ratsnake, Texas (Pantherophis obsoletus), 191 as nest predator of Mississippi Kite, 190 as songbird nest predator, 139, 143–144 Raven, Common (Corvus corax), as nest predator, 73 redcedar, Eastern (Juniperus virginiana), 107 red fire ants. See ants, fire (Solenopsis invicta) Redhead (Aythya americana), 40 camera studies of, 37 parasitic egg-laying and, 38 remnant prairie, 107 bird productivity and nest predation in, 119, 121–131 conservation of, 120 study of nest defense by passerines in, 150 reproductive strategies, video surveillance and, 38, 39 reptiles, as nest predators, 11 researchers forced/premature fledging and, 7–8 impact of activity around nest and, 14–15 restlessness in incubation, 94, 95, 96, 97 Ringtail (Bassariscus astutus), as nest predator, 139 robel pole, 123

Sage-Grouse, Greater (Centrocercus urophasianus) incubation attentiveness and, 72–73 nest predation of, 37, 39 nest recess in, 83 sand track stations, 122–123 Sandpiper, Semipalmated (Calidris pusilla), incubation behavior of, 91, 93, 95, 96, 97, 98, 101 Sandpiper, Upland (Bartramia longicauda) nesting habitat, 130 nest survival of, 123, 125 Sandpiper, White-rumped (Calidris fuscicollis) egg neglect among, 99 incubation behavior of, 91, 93, 94–97, 98, 100, 101 Saskatchewan identification of Sprague’s Pipit nest predators in, 174–181 incubation behavior of Sprague’s Pipit in, 68–74 SAS software, 80, 165 Schizchyrium scoparium. See bluestem, little (Schizchyrium scoparium) Sciurus niger. See squirrel, fox (Sciurus niger) Scolopax minor. See Woodcock (Scolopax minor) Scopus, 186 Scotophis, as nest predator, 157 Screech-Owl, Eastern (Megascops asio), nest parasitism and, 38–39 Scrub-Jay, Western (Aphelocoma californica), as nest predator, 139, 144 SD cards, 187, 188 Seirus aurocapillus. See Ovenbird (Seiurus aurocapillus) Setophaga caerulescens. See Warbler, Black-throated Blue (Setophaga caerulescens) Setophaga chrysoparia. See Warbler, Golden-cheeked (Setophaga chrysoparia) Setophaga discolor. See Warbler, Prairie (Setophaga discolor) Setophaga kirtlandii. See Warbler, Kirtland’s (Setophaga kirtlandii) sex nest abandonment and, 162, 168 nest recess length and, 80, 81, 82, 83 shifts in orientation on nest, 111 shorebirds, influence of weather on incubation in, 89–101 shrubland passerines, nocturnal activity of nesting, 105–114 shrub nests fire ant predators and, 145 predation risk and, 139, 140, 141, 142 Sigmodon hispidus. See rat, Hispid cotton (Sigmodon hispidus) skunk, striped (Mephitis mephitis) as bobwhite nest predator, 163 as grassland passerine nest predator, 9, 10, 128 as Sprague’s Pipit nest predator, 173, 176, 179, 180 as waterfowl nest predator, 28

INDEX

219

Skutch hypothesis, 12 sleep back, 106, 108, 110 front, 106, 108 postures for, 105 unihemispheric, 106, 108 smart systems, for video surveillance, 42 snakes. See also individual species as dominant nest predators in southern habitats, 26, 27 indirect control of, 29 nest defense against, 15, 16, 149, 153–158 as nest predators, 8, 9, 11, 26, 27, 120, 127, 130, 135, 139, 143–144, 152–153, 154 snake, corn (Pantherophis guttatus guttatus), as bobwhite predator, 165 Snipe, Wilson’s (Gallinago delicata), 39 solar power system, for video surveillance system, 62, 63, 194 Solenopsis invicta. See ant, fire (Solenopsis invicta) Solidago spp. See goldenrod (Solidago spp.) Sparrow, Baird’s (Ammodramus bairdii) hatching and fledging times, 50, 51, 52, 53, 54 nest fate and, 6 parental behavior and, 17 response to severe weather, 18 Sparrow, Clay-colored (Spizella pallida) hatching and fledging times for, 47, 50, 51, 52–58 human observers and forced fledging, 7–8 nest defense and, 16 nest failure of, 5 nest fate and, 6 nestling fate, 5, 7 nest height and damage by predator, 14 parental behavior and, 17 as part of a North Dakota grassland bird community, 24 Sparrow, Field (Spizella pusilla) nest defense against snakes by, 155, 156 nocturnal activity of nesting, 105, 107–114 as part of a Missouri shrubland and forest bird community, 25 Sparrow, Grasshopper (Ammodramus savannarum) edges and nest survival of, 119, 126–127, 130–131 fledging age, 52, 53, 54, 56, 57 nest defense against snakes by, 155 nest fate and, 6 nesting habitat, 119, 125, 130 nesting period of, 123 nest survival of, 125–127, 130–131 nocturnal activity of nesting, 105, 107–114 parental behavior of, 17 as part of a Wisconsin grassland bird community, 24 productivity of, 119, 125 Sparrow, Henslow’s (Ammodramus henslowii) helper at nest and, 17 male feeding of chicks, 114 nest defense by, 152, 155, 156 nest success of, 125 nesting habitat, 119, 125, 130 nesting period, 123

220

STUDIES IN AVIAN BIOLOGY

Sparrow, Le Conte’s (Ammodramus leconteii) hatching and fledging times, 50, 53 nest fate and, 6 Sparrow, Savannah (Passerculus sandwichensis) forced fledging among, 7 hatching and fledging times for, 50, 51, 52, 53, 54–56, 57–58 nest defense against snakes by, 155 nest fate and, 6 nest predator identification and, 14, nest survival of, 125 nesting habitat of, 125, 130 nesting period of, 123 as part of North Dakota and Wisconsin grassland bird communities, 24 premature fledging among, 5, 7 Sparrow, Song (Melospiza melodia) forced fledging among, 53, 56 nest defense against snakes by, 155, 156 nest fate and, 6 nocturnal activity of nesting, 106 Sparrow, Tree (Spizella arborea) incubation attentiveness and, 73 nocturnal activity of nesting, 106 Sparrow, Vesper (Pooecetes gramineus) edges and nesting success, 131 hatching and fledging times, 50, 51, 52, 53, 54 nest fate and, 6 nesting habitat of, 125 as part of a North Dakota grassland bird community, 24 Sorghastrum nutans. See grass, Indian (Sorghastrum nutans) soybeans (Glycine max), 121, 150 Spearman’s rank correlation, 109 Spizella arborea. See Sparrow, Tree (Spizella arborea) Spizella pallida. See Sparrow, Clay-colored (Spizella pallida) Spizella pusilla. See Sparrow, Field (Spizella pusilla) squirrel, fox (Sciurus niger), as nest predator, 139 still-frame cameras, 192 Stipa spartea. See grass, needle (porcupine) (Stipa spartea) Strategic Habitat Conservation, 30 Sturnella magna. See Meadowlark, Eastern (Sturnella magna) Sturnella neglecta. See Meadowlark, Western (Sturnella neglecta) Swan, Trumpeter (Cygnus buccinator) camera studies of, 37 nest defense by, 38 system power, improvements needed in video surveillance, 42 Tall Timbers Research Station and Land Conservancy, 78, 79, 163 Taxidea taxus. See badger, American (Taxidea taxus) telemetry homing techniques, 79 temperature nest recess and, 83–84, 85 snakes as predators and, 8 temporal factors, nest survival and, 136–137, 138, 141, 143, 146

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testosterone, 84 Texas nest predator identification and nest predation patterns in, 135–146 passerine nest predation in, 24–27 Texas Ecological Systems Classification Project map, 138 Thamnophis radix. See gartersnake, Plains (Thamnophis radix) Thamnophis sirtalis. See gartersnake, common (Thamnophis sirtalis) Thamnophis spp. See gartersnake (Thamnophis spp.) theoretical decision model, for incubating/brooding birds, 151 thermistor probes, 91 thistle (Cirsium and Carduus spp.), 121 Thomas County (Georgia), 78 Thomomys talpoides. See gopher, northern pocket (Thomomys talpoides) Thrasher, Brown (Toxostoma rufum), as part of a Georgia forest bird community, 25 Thrush, Wood (Hylocichla mustelina), as part of a Missouri shrubland and forest bird community, 25 Thryothorus ludovicianus. See Wren, Carolina (Thryothorus ludovicianus) time-lapse video recording systems, 4, 185, 189 time of day incubation attentiveness and, 69–71, 73–74 predation occurs, 3, 8–9, 12, 19 Sprague’s Pipit nest predation and, 176, 177 time of final return to nest, 109, 110 time of waking, 111, 112, 113 Titmouse (Baeolophus spp.), 150 Tits, Great (Parus major) nocturnal activity of nesting, 113 photos of prey in bills of, 185 Tits, Marsh (Parus palustris), fledging, 58 Towhee, Eastern (Pipilo erythrphthalmus), as part of a Georgia forest bird community, 25 Toxostoma rufum. See Thrasher, Brown (Toxostoma rufum) trail cameras, 192 Troglodytes aedon. See Wren, House (Troglodytes aedon) Turkey, Wild (Meleagris gallopava) camera studies of, 37 nest attendance among, 84 nest predation in, 38 Turnstone, Ruddy (Arenaria interpres), incubation behavior of, 91, 93, 95, 96, 97, 98, 101 Tympanuchus cupido. See Prairie-Chicken, Greater (Tympanuchus cupido) Tympanuchus pallidicinctus. See Prairie-Chicken, Lesser (Tympanuchus pallidicinctus) unihemispheric sleep, 106, 108 uniparental incubation, 90 biparental incubation vs., 93–94 diel patterns of, 89, 94, 96 monitoring, 91, 92 recesses and, 94, 96, 98, 100 restlessness and, 97 temporal and weather-related effects on, 94–99 U.S. Fish and Wildlife Service, 30

urbanization, predation risk and, 141 Urocitellus richardsonii. See ground squirrel, Richardson’s (Urocitellus richardsonii) Urocyon cinereroargenteus. See fox, gray (Urocyon cinereoargenteus) Ursus arctos middenorffi. See bear, brown (Ursus arctos middenorffi) user-built digital video systems, 189 case studies, 186–188, 190–191 components, 187 schematic, 187 vendor-built vs., 195–196 vendor-built video systems, user-built vs., 195–196 Vermivora pinus. See Warbler, Blue-winged (Vermivora pinus) video surveillance systems batteries, 4, 187, 188, 194 for bobwhite nests, 163–164 cables and connectors, 194–195 cameras for use with DVRs, 193–194 case studies, 186–188, 190–191 development of camera technology for monitoring nests, 185–196 effect on birds/nests, 5, 6, 7, 18, 64, 196 gamebirds and, 35–43 for identification of Sprague’s Pipit nest predators, 174–175 to identify nest predators, 3–19, 174 image-recording units, 191–193 LCD viewing monitor, 193, 195 limitations of, 18–19 literature review on use of, 189, 190 monitoring grassland passerine nests, 4–5 for monitoring hatching and fledging times, 49 monitoring Sprague’s Pipit incubation behavior using, 68–74 nest defense study and, 150, 152–153, 157, 158 nest predator identification using, 8–12, 64–65, 131, 137, 173–181 nocturnal activity of nesting shrubland and grassland passerines, 107 for Northern Bobwhite, 79 objective of, 136 for predator identification and nest predation patterns, 137 reduction of nest predation risk and, 64–65 for shorebird incubation behavior, 91–92 study of nesting birds and, xiii–xv subsampling data, 73–74 technological advances needed to improve, 40–43 user- vs. vendor-built systems, 195–196 for Western Meadowlark nests, 62–63 vigils, 105, 106, 108, 109, 113 Vireo, Black-capped (Vireo atricapilla), 28 habitat, 136 nest predation patterns and nest success of, 136–146 as part of a Texas forest and shrubland bird community, 25 Vireo, Least Bell’s (Vireo bellii pusillus), 28 Vireo, White-eyed (Vireo griseus), nest survival among, 140

INDEX

221

voles (Microtus spp.) as nest predator, 9, 10, 128 as Sprague’s Pipit nest predator, 173, 175–176, 179 Vulpes spp. See fox (Vulpes spp.) Vulpes vulpes. See fox, red (Vulpes vulpes) waking time, 111, 112, 113 body size and, 113 walk in tunnel traps, 79 Warbler, Black-throated Blue (Setophaga caerulescens), incubation attentiveness and, 71 Warbler, Blue-winged (Vermivora pinus) habitat of, 107 nocturnal activity of nesting, 105, 107–114 Warbler, Golden-cheeked (Setophaga chrysoparia) habitat, 136 nest predation patterns and nest success of, 136–146 as part of a Texas forest and shrubland bird community, 25 Warbler, Kentucky (Oporornis formosus), as part of a Missouri shrubland and forest bird community, 25 Warbler, Kirtland’s (Setophaga kirtlandii), conservation efforts for, 28 Warbler, Prairie (Setophaga discolor), nocturnal activity of nesting, 105, 106, 107–114 Warbler, Worm-eating (Helmitheros vermivorus), as part of a Missouri shrubland and forest bird community, 25 warm-season grasses, 25 waterfowl mesopredators and, 27–28 nest abandonment following partial depredation and, 167, 169 nest searches, 74 partial depredation of nests and, 161, 167, 169

222

STUDIES IN AVIAN BIOLOGY

weasel (Mustela spp.), as nest predator, 9, 10, 128 weasel, least (Mustela nivalis), as nest predator, 9, 10 weasel, long-tailed (Mustela frenata) nest defense against, 15, 16 as nest predator, 9, 10 weather influence on shorebird incubation, 89–101 nocturnal behavior and, 109, 113 parental and nestling reactions to, 17–18 wide-dynamic range cameras, 194 Windows Media Player 11, 188 wiregrass (Aristida stricta), 163 Wisconsin bird productivity and nest predation in, 121–131 nest defense by passerines in, 150–158 nest predators of grassland passerines in, 10–11 nocturnal activity of grassland passerines in, 107–114 Woodcock (Scolopax minor), 39 Wren, Carolina (Thryothorus ludovicianus), nocturnal activity of nesting, 113 Wren, House (Troglodytes aedon) fledging time of, 58 nocturnal activity of nesting, 106, 113 Xanthocephalus xanthocephalus. See Blackbird, Yellowheaded (Xanthocephalus xanthocephalus) Yellowthroat, Common (Geothlypis trichas) hatching time, 50 nest fate and, 6 Zapus spp. See mouse, jumping (Zapus spp.) Zea mays. See corn (Zea mays)

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STUDIES IN AVIAN BIOLOGY

1. Kessel, B., and D. D. Gibson. 1978. Status and Distribution of Alaska Birds.

14. Sealy, S. G., editor. 1990. Auks at Sea.

2. Pitelka, F. A., editor. 1979. Shorebirds in Marine Environments.

15. Jehl, J. R., Jr., and N. K. Johnson, editors. 1994. A Century of Avifaunal Change in Western North America.

3. Szaro, R. C., and R. P. Balda. 1979. Bird Community Dynamics in a Ponderosa Pine Forest. 4. DeSante, D. F., and D. G. Ainley. 1980. The Avifauna of the South Farallon Islands, California. 5. Mugaas, J. N., and J. R. King. 1981. Annual Variation of Daily Energy Expenditure by the Black-billed Magpie: A Study of Thermal and Behavioral Energetics. 6. Ralph, C. J., and J. M. Scott, editors. 1981. Estimating Numbers of Terrestrial Birds. 7. Price, F. E., and C. E. Bock. 1983. Population Ecology of the Dipper (Cinclus mexicanus) in the Front Range of Colorado. 8. Schreiber, R. W., editor. 1984. Tropical Seabird Biology. 9. Scott, J. M., S. Mountainspring, F. L. Ramsey, and C. B. Kepler. 1986. Forest Bird Communities of the Hawaiian Islands: Their Dynamics, Ecology, and Conservation. 10. Hand, J. L., W. E. Southern, and K. Vermeer, editors. 1987. Ecology and Behavior of Gulls.

16. Block, W. M., M. L. Morrison, and M. H. Reiser, editors. 1994. The Northern Goshawk: Ecology and Management. 17. Forsman, E. D., S. DeStefano, M. G. Raphael, and R. J. Gutiérrez, editors. 1996. Demography of the Northern Spotted Owl. 18. Morrison, M. L., L. S. Hall, S. K. Robinson, S. I. Rothstein, D. C. Hahn, and T. D. Rich, editors. 1999. Research and Management of the Brown-headed Cowbird in Western Landscapes. 19. Vickery, P. D., and J. R. Herkert, editors. 1999. Ecology and Conservation of Grassland Birds of the Western Hemisphere. 20. Moore, F. R., editor. 2000. Stopover Ecology of Nearctic–Neotropical Landbird Migrants: Habitat Relations and Conservation Implications. 21. Dunning, J. B., Jr., and J. C. Kilgo, editors. 2000. Avian Research at the Savannah River Site: A Model for Integrating Basic Research and Long-Term Management.

11. Briggs, K. T., W. B. Tyler, D. B. Lewis, and D. R. Carlson. 1987. Bird Communities at Sea off California: 1975 to 1983.

22. Scott, J. M., S. Conant, and C. van Riper, II, editors. 2001. Evolution, Ecology, Conservation, and Management of Hawaiian Birds: A Vanishing Avifauna.

12. Jehl, J. R., Jr. 1988. Biology of the Eared Grebe and Wilson’s Phalarope in the Nonbreeding Season: A Study of Adaptations to Saline Lakes.

23. Rising, J. D. 2001. Geographic Variation in Size and Shape of Savannah Sparrows (Passerculus sandwichensis).

13. Morrison, M. L., C. J. Ralph, J. Verner, and J. R. Jehl, Jr., editors. 1990. Avian Foraging: Theory, Methodology, and Applications.

24. Morton, M. L. 2002. The Mountain White-crowned Sparrow: Migration and Reproduction at High Altitude.

223

25. George, T. L., and D. S. Dobkin, editors. 2002. Effects of Habitat Fragmentation on Birds in Western Landscapes: Contrasts with Paradigms from the Eastern United States.

35. Spear, L. B., D. G. Ainley, and W. A. Walker. 2007. Foraging Dynamics of Seabirds in the Eastern Tropical Pacific Ocean.

26. Sogge, M. K., B. E. Kus, S. J. Sferra, and M.J. Whitfield, editors. 2003. Ecology and Conservation of the Willow Flycatcher.

36. Niles, L. J., H. P. Sitters, A. D. Dey, P. W. Atkinson, A. J. Baker, K. A. Bennett, R. Carmona, K. E. Clark, N. A. Clark, C. Espoz, P. M. González, B. A. Harrington, D. E. Hernández, K. S. Kalasz, R. G. Lathrop, R. N. Matus, C. D. T. Minton, R. I. G. Morrison, M. K. Peck, W. Pitts, R. A. Robinson, and I. L. Serrano. 2008. Status of the Red Knot (Calidris canutus rufa) in the Western Hemisphere.

27. Shuford, W. D., and K. C. Molina, editors. 2004. Ecology and Conservation of Birds of the Salton Sink: An Endangered Ecosystem. 28. Carmen, W. J. 2004. Noncooperative Breeding in the California Scrub-Jay. 29. Ralph, C. J., and E. H. Dunn, editors. 2004. Monitoring Bird Populations Using Mist Nets.

37. Ruth, J. M., T. Brush, and D. J. Krueper, editors. 2008. Birds of the US–Mexico Borderland: Distribution, Ecology, and Conservation.

30. Saab, V. A., and H. D. W. Powell, editors. 2005. Fire and Avian Ecology in North America.

38. Knick, S. T., and J. W. Connelly, editors. 2011. Greater Sage-Grouse: Ecology and Conservation of a Landscape Species and Its Habitats.

31. Morrison, M. L., editor. 2006. The Northern Goshawk: A Technical Assessment of Its Status, Ecology, and Management.

39. Sandercock, B. K., K. Martin, and G. Segelbacher, editors. 2011. Ecology, Conservation, and Management of Grouse.

32. Greenberg, R., J. E. Maldonado, S. Droege, and M. V. McDonald, editors. 2006. Terrestrial Vertebrates of Tidal Marshes: Evolution, Ecology, and Conservation. 33. Mason, J. W., G. J. McChesney, W. R. McIver, H. R. Carter, J. Y. Takekawa, R. T. Golightly, J. T. Ackerman, D. L. Orthmeyer, W. M. Perry, J. L. Yee, M. O. Pierson, and M. D. McCrary. 2007. At-Sea Distribution and Abundance of Seabirds off Southern California: A 20-Year Comparison. 34. Jones, S. L., and G. R. Geupel, editors. 2007. Beyond Mayfield: Measurements of Nest-Survival Data.

Indexer: Composition: Text: Display: Printer and Binder:

40. Forsman, E. D., et al. 2011. Population Demography of Northern Spotted Owls. 41. Wells, J. V., editor. 2011. Boreal Birds of North America: A Hemispheric View of Their Conservation Links and Significance. 42. Paul, E., editor. 2012. Emerging Avian Disease. 43. Ribic, C. A., F. R. Thompson III, and P. J. Pietz, editors. 2012. Video Surveillance of Nesting Birds.

Robie Grant MPS Limited 9.25/11.75 Scala Scala Sans, Scala Sans Caps Thomson-Shore

TABLE 1.1 Fates of 188 grassland passerine nests monitored with video surveillance systems in North Dakota and Minnesota during 1996–2001.

Destroyed Common name

Scientific name

Total nests

Common Yellowthroat

Geothlypis trichas

1

Clay-colored Sparrow

Spizella pallida

Vesper’s Sparrow

Pooecetes gramineus

Savannah Sparrow

Passerculus sandwichensis

Grasshopper Sparrow

Depredated

Other

Other loss

Censored

Fledged

2

1

6

34

8

26

1 15

17

59

9

15

Ammodramus savannarum

4

1

Baird’s Sparrow

Ammodramus bairdii

3

1

Le Conte’s Sparrow

Ammodramus leconteii

2

Song Sparrow

Melospiza melodia

2

1

1

Chestnut-collared Longspur

Calcarius ornatus

9

2

4

3

Bobolink

Dolichonyx oryzivorus

23

7

4

12

Red-winged Blackbird

Agelaius phoeniceus

Western Meadowlark

Sturnella neglecta

Total nests

75

Abandoned

6

4

2 1

3 1

1 1

1

1

1

3

2

1

88

37

49

3

2

14

83

NOTES: Nest abandonment