Introduction to the Natural History of the San Francisco Bay Region [Reprint 2020 ed.] 9780520319370

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California Natural History Guides: i

INTRODUCTION TO THE

NATURAL HISTORY OF THE SAN FRANCISCO BAY REGION BY

ARTHUR C. SMITH DRAWINGS BY GENE M. CHRISTMAN

UNIVERSITY OF CALIFORNIA PRESS B E R K E L E Y , LOS ANGELES, LONDON

UNIVERSITY OF CALIFORNIA PRESS BERKELEY AND LOS ANGELES, CALIFORNIA UNIVERSITY OF CALIFORNIA PRESS, LTD. LONDON, ENGLAND

© 1959

BY

THE REGENTS OF THE UNIVERSITY OF CALIFORNIA F I F T H PRINTING, 1 9 7 4

ISBN:

0-520-01185-6

LIBRARY OF CONGRESS CATALOG CARD NUMBER:

59-6051

PRINTED IN THE UNITED STATES OF AMERICA DESIGN BY JOHN B. GOETZ

CONTENTS INTRODUCTION

5

T H E S A N F R A N C I S C O B A Y REGION

7

LIVING THINGS

14

B I O T I C C O M M U N I T I E S OF THE B A Y REGION

22

T H E C O M M U N I T Y OF NATURE

32

N A T U R E ACTIVITIES

45

SEEING NATURE IN THE B A Y REGION

60

W H E R E TO OBTAIN H E L P

66

SUGGESTED REFERENCES

71

ILLUSTRATIONS ON COVER

Ceanothus Silk Moth (Hyalophora euryalus) Fly Agaric (Amanita muscaria) Mountain Lilac (Ceanothus thyrsiflorus) American Avocet (Recurvirostra americana)

INTRODUCTION Most of us are interested in the world around us. W e wish that we knew the name of the beautiful bird that sings on the back fence every morning; we wonder what kind of a shell it was that we picked up at the beach last Sunday; or perhaps we would like to know if that small but ferocious-looking creature we found under a rock in the back yard is really as dangerous as it looks. All too often it is just too much trouble to find the answer, and we soon forget all about it. This series of California Natural History Guides will help you find the answers to these and many other questions about the natural history of the back yards and vacant lots of our towns and cities; the mountains, valleys, ponds, streams, deserts and beaches of California. You may find that some phase of nature study will provide just the added interest you have been seeking to make life more enjoyable. If you are a hunter or fisherman, you may want to learn more of the nongame animals that you see on your trips afield. If you are a teacher, youth leader, or student, you may wish to increase your store of facts about plants and animals around school, camp, or home. If you are a member of a youth organization, you may want help in qualifying for merit badges or other awards in nature subjects. If you have recently moved to this area, you may find the plants and animals so different from those you have known before that you are uncertain of your identifications. This series of guides will help [5]

you to identify the common plants and animals of this region. Whether you are eight or eighty, you will find life more enjoyable if you become familiar with nature in the bay region. Studying and observing nature can be a highly satisfying yet economical year-around recreation for the entire family. Spring, summer, fall, and winter your family car can take you (with your California Natural History Guide in hand) to beaches, mountains, fields, and marshes where you can become acquainted with the birds, butterflies, shells, rocks and minerals, trees, flowers or other interesting subjects of your choice. At first you will be content to learn their names. Later you will want to know, for example, where the birds nest, where to look for cocoons and chrysalids, or how to identify and preserve animal tracks. If you make careful observations and keep accurate notes, you may find that you can make worthwhile contributions to science, for the habits and the details in the life histories of many of our bay region animals are still unknown. In this, the first volume of the series, there is a general introduction to the San Francisco Bay region —its physical features, climate, and seasons. This is followed by discussions of the characteristics of living things, common and scientific names of plants and animals, and the interrelationships in the world of nature. Special sections describe the biotic communities where plants and animals are found and suggest interesting field trips you can take in the bay region. Various nature activities are discussed, and organizations concerned with nature in the bay region are listed.

[6]

T H E SAN FRANCISCO BAY REGION PHYSICAL DESCRIPTION

In the California Natural History Guides the bay region is arbitrarily designated as the nine counties bordering San Francisco Bay plus Santa Cruz County. Although the entire bay is generally called San Francisco Bay, the north part is known as San Pablo Bay, and its narrow easterly extension beyond Carquinez Strait as Suisun Bay. The bay opens to the Pacific Ocean through the Golden Gate; covers a total area of some 900 square miles extending from Treasure Island approximately 30 miles to the southeast and 20 miles to the north; and reaches eastward from San Pablo Bay some 30 miles through Carquinez Strait along the drowned river valley of the Sacramento-San Joaquin rivers. The bay varies from 3 to 13 miles in width (narrowing to half a mile at Carquinez Strait) with the main channel from 20 to 60 feet deep south of the Bay Bridge; from 30 to 130 feet deep between Treasure Island and Angel Island; from 220 to 357 feet deep beneath Golden Gate Bridge; varying from 20 to 54 feet from Treasure Island to San Pablo Strait; and with a maximum channel depth of 34 feet in San Pablo Bay (most of which is less than 10 feet deep). Carquinez Strait varies in depth from 94 feet at Carquinez Bridge to 38 feet at Martinez Yacht Harbor. A number of small islands rise in the bay, mostly in the area bounded by the three major bridges. The San Francisco and Marin peninsulas enclose the bay from the west, with Mount Tamalpais (2,604 ft.) dominating the Marin Peninsula, and the Montara and northern extension of the Santa Cruz Mountains [7]

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