2 26 Distrihutioji of Land Birds, [zoe 



-I 



eastern one in the interior. This interior Boreal Area has a tend- 

 ency to isolate the two areas of the Sonoran Province. 



As above remarked, these two great provinces have representa- 

 tives of four sub-regions or areas in Cahfornia, two being Boreal 

 and two Sonoran in character. The territory occupied by the Coast 

 Range of mountains, south nearly to latitude thirty -six degrees, 

 forms one area which extends north to Alaska, and called bv Dr. 

 Merriam on his provisional map of North American life areasf the 

 Pacific Coast Area. The other Boreal Area, which unites with the 

 preceding in the northern part of the State, is restricted to the great 

 interior range, the Sierra Nevada, and has a very characteristic bird 

 fauna. Dr. Merriam gives us no specific name for this sub-region, 

 but it seems to be so strongly marked as to warrant one, and for 



present purposes at least, the name Sierra Nevada Area may be 

 used, 



h 



Of the Sonoran Province, the Sonoran Area, occupying the entire 

 southeastern portion of the State, is the most strongly marked. It 

 includes both the Colorado Valley and Desert Region of Cooper, 

 and is the most distinctive area of the State. North of latitude 

 thirty-six degrees the Great Basin Area enters our territory on a 

 very narrow region east of the Sierra Nevada Mountains. This is 

 also the fauna of the extreme northeastern corner of the State, but 

 its presence within our limits is so restricted that it need only be 

 considered as an incidental feature. According to Dn Merriam's 

 map, the Sonoran Area extends quite to the coast south of latitude 

 thirty-five degrees, while all that is left of the Sonoran Province 

 (the great interior valleys and coast region between latitudes thirty- 







So far 



as the bird fauna is concerned, and I think the same will apply to all 

 forms of life, the distinctive features of the Sonoran Area seem to 

 be lost after reaching the Coast Range. This would leave a narrow 

 strip of the southern coast area to be added to the Californian Area, 

 apparently. But in considering the avifauna of the southern coast 

 region from the southern boundary of the State north to latitude 

 thirty-eight degrees, I find that It Is made up of some forms charac- 

 teristic of each area in the State, and the natural conclusion is that 

 it is a transition or intermediate region, and it may properly be call- 



tNorth American Fauna, No. 3, Map 5. 



