258 Distribution of Land Birds. [ZOE 
breed elsewhere, while a still greater number occur only in the Sierra 
Nevada Area. te 
The Pacific Coast Area extend a little fo the south of Monterey 
Bay, and thence north to Alaska. _ It first attains its most distinctive 
features in the extreme north of California, where a number of ex- 
tremely deeply colored races begin to thake their appearance. As 
we go northward through Oregon, Washington, and British Colum- 
bia, these deeply colored races increase in number and intensity. 
Among the varieties characteristic. of this region may be mentioned’ 
the northwestern flicker, Stellar’s jay and the chestnut-backed 
chickadee. It seems to me, however, that the territory inhabited by 
such dark races as the above should not necessarily be considered 
as a distinct faunal area; for these forms are of such recent origin 
that they are not sufficiently well marked in character or in the 
limits of their distribution to mark the bounderies of an area. All 
of these northern varieties shade insensibly into the forms occurring © 
to the south of them. Thus, I have never seen a typical specimen 
of Stellar’s jay from northern California, although it is the ‘race 
ascribed to that region. These dark races seem to be directly de- 
pendent upon the abundance of rain fall which increases as we go 
north from California. Accordingly, in defining the southern limit 
of this area we should look to some more stable species, for a faunal 
area ought to have at least a few distinct species which are charac- 
teristic of it. There is, perhaps, no species which will better serve 
to mark the limits of the Pacific Coast Areain California than Vaux’s 
swift. This species is a migrant in the southern part of the State, 
but breeds from the Santa Cruz Mountain region on the south, 
north along the coast into British Columbia. I have observed it at 
several localities during the breeding season, and it has always been 
in or near the redwoods. ‘There are a number of species and vari- 
eties characteristic of the Pacific Coast Area (some of which also 
occur in the Sierra Nevada Area), which are always sure tobe met 
with on entering a redwood forest which are seldom seen away from _ 
this tree. Besides the blue-fronted Jay and Vaux’s swift, which have 
already been alluded to, might. be mentioned Cassin’s vireo, Mac- 
gillivray’s warbler, western creeper, and California chickadee. 
The following table gives a list of the 
characteristic species of — 
both areas of the Boreal Province: ae ee ne ee 
