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62 THE CONDOR [ Vol. II Land Birds of Marin County, Cal. BY jos. MAILLIARD, SAN GERONIl?,IO, CAL. Among the many counties in this large state, Marin county occupies a somewhat unique position, its situation being similar to only one other. This is San Fran- cisco county, which being very small, covering not much more than tire city lim- its, cuts but little figure ornithologically. Marin itself is one of the smallest 'counties in the state, yet it has a considerable area, being somewhat in the shape af a diamond with the longer diagonal about forty-three miles and the shorter thirty. The peculiarity of its position lies in the fact that on three sides of the diamond is salt water. Three-fourths of its boundary is coast line, the actual contour of the shore probably making it more than five-sixths of the total. The western and south-western sides are washed by the Pacific Ocean while San Francisco Bay limits the eastern. As its short northern side is not near any large valley or river it is practically cut off from any direct natural line of north and south mi- gration. All birds flying into the county from the south have to cross San Fran- cisco Bay, while those migrating south must cross it when they leave. In con- sequence of this those birds which do not make long, strong flights seem only to wander in from their regular routes more in the manner of stragglers than of regular migrants. For instance, tire big flight of Louisiana Tanagers in r896 which was notable throughout the state, only touched this county to a slight extent, but very few birds having been noticed. Yet many of the regular immigrants must cross the bay, for at the period of the first spring migrations, they are seen in the southern part, where it is warmer, sometimes two or three weeks before they arrive in the interior. These first arrivals appai'ently come over from San Francisco or Ala- meda county. It is possible that sonre birds, like the Helminlhophi/a c. lutescerts for instance, may come in from Sonoma county on the north and follow the warmer bay shore until they reach the southern extremity of Marin county be- fore ventu['ing into the interior, but there are no observers in the right spots to determine this. The county is for the most part exceedingly hilly, almost mountainous, and a -large proportion of its area is cc, vered with either timber or brash. Of the tim- bered areas there are three divisions; the redwood, which is intermingled with and runs into fir, bay, madtone etc.; the pine and the oak regions. Each has a bird life peculiar to itself, yet there are certain birds common to all. The red- wood region and innnediate vicinity contains by far the majority of (l,anocilta s. ./?ontalis, Certhia f. occidentalis and ,4nor/brita h. pacificus for instance. The pine region harbors the Sitta p.l?g'ma, a ahnost exclusively, while the oak region, which is like parts of Sonoma county and in fact is an extension of that county's oak region, is inhabited by the Sitta c. aculeata, ]arus iJwrnatus etc. The brushy areas are also of several distinct kinds, but these merge into one another more or less, and with the exception of perhaps the sage, cyanothus and salmon berry regions, need not be considered as having peculiar avifauna. And indeed these three onlS- seem to be attractive to certain birds at certain seasons. For example, if that occasional winter visitant, the Passerella i. megark?,nch?,t, is here at all it is only found on the tops of the hills among the cyanothus. Again in the spring the ,4imophila rt?ficeps is found and probably breeds in the sage t)rush, and yet in late summer may be observed among poison oak bushes and black- berry vines on grassy hillsides far away from the sage. The temperature, especially in winter, varies a great deal in different parts of the county, and the habits of the birds vary accordingly. The bay sirore enjoys a much more equable winter temperature than the interior, in consequence of which House Finches and Hummingbirds may be found all winter in San Ra- fael, which is on the edge of a salt water nmrsh, while never found during l)e-