1 88 Bird -Lore 



DECEMBER AND JANUARY BIRD-LIFE ON EASTERN SIDE OF SAN FRANCISCO BAY 



By Charles Keeler 



To describe the bird life of California within the limits of the 

 present series of sketches would be an impossible task. This great 

 state, stretching in a broad band along the Pacific coast, diversified 

 as it is by two long mountain ranges extending in a general northerly 

 and southerly trend, embracing a wide interior valley and cutting off 

 the district to the east, which is left an arid waste, contains a greater 

 number of faunal zones than any other region of corresponding size 

 on the American continent. In the valleys the rigors of an eastern 

 winter are unknown ; in the mountains the snow-drifts are as deep 

 as in Canada. Even in so restricted a section as the San Francisco 

 Bay region there is considerable diversity in fauna and flora. Upon 

 the western side of the bay, and more particularly on the north- 

 western shore, the redwood forests determine to a large extent the 

 distribution of both plants and birds, while on the eastern shore the 

 redwoods are confined to one or two restricted pockets in the hills. 

 It is to the birds of this eastern side that I shall confine my obser- 

 vations. The hills here rise to a height of a thousand feet or more, 

 with a gently descending plain at their base, reaching down to the 

 bay shore two or three miles away. These hills are treeless save 

 where forests of eucalyptus have been planted and are covered with 

 grass and chaparral. In the little cafions which cut through the 

 range at frequent intervals are groves of superb live-oak trees in 

 the lower reaches and laurel, scrub oak and alders higher up. 



In the severest winter weather the thermometer seldom falls as 

 low as 25°, and, frosty mornings are the exception. Rain falls at 

 more or less frequent intervals during this season, but showers 

 are almost unknown during the summer months. As a consequence 

 of the mildness of the winters, birds are quite as abundant 

 at this time of year as at any other, and the list of permanent 

 residents is comparatively large. Some among these, such as 

 the California Brown Towhee, Spurred Towhee, the Green-backed 

 or Arkansas Goldfinch, Plain-crested Titmouse, Wren-Tit, California 

 Bush-Tit, California Jay, Anna's Hummingbird, Western Meadow- 

 lark, Samuel's Song Sparrow, and the Red-shafted Flicker, are, so 

 far as I can detect, permanent residents. By this I mean that there 

 seems to be no evidence that the individuals which nest here go 

 away for the winter to be replaced by others of the same species. 

 Of course this is a difficult point to prove, but there is every indica- 

 tion of stability with these species. They are found in about the same 

 places all the year round, and at no one season do they seem more 

 abundant than at another. To have learned to distinguish them 



