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A BIOLOGICAL JOURNAL 



Vol. L OCTOBER, 1S90. No. S. 



THE GEOGRAPHICAL DISTRIBUTION OF LAND BIRDS 



IN CALIFORNIA. 



BY CHARLES A. KEELER. 



California is of more than usual interest to the student of the geo- 

 graphical distribution of animals, from the fact that within its limits 

 there are at least four distinct life areas represented; a circumstance 

 which, I believe, does not occur within any like extent of territory 

 in the United States. Some years ago Dr, J, G. Cooper published 

 a paper on '*The Fauna of California and its Geographical Distrib- 

 ution/'* and although it is still of great value, the extensive notes 

 and observations which have been made on our avifauna since that 

 day throw much new light on this subject. Then^ too, Dr. Mer- 

 riam, in a recent bulletin of the United States Department of Agri- 

 culture, '* Fauna, No. 3/* modifies all previously existing theories 

 on the distribution of animals in North America. Thus it seems 

 desirable, in the light of new facts and new theories, to reconsider 

 the distribution of our birds. 



The principal change from the life areas given by Dr. Cooper 



consists in uniting certain regions which he considered as separate; 



as for example, his Colorado Valley and Desert Region, and his 

 Southern and Northern Sierra Region." Considering the hasty and 

 incomplete survey of our fauna which had been made at that day, it 

 is remarkable that his regions should coincide as closely as they do 

 with those now recognized. As pointed out by Dr. Merriam,t all 

 life areas in extra tropical North America may be divided into two 

 great provinces — the Boreal and the Sonoran; and we find that Cal- 

 ifornia forms no exception to this rule. The Boreal Province sends 

 down two long narrow interpenetrating arms witli a general north 

 and south trend, the western one lying along the coast, and the 



•Proc. CaL Acad. Sci. iv, pp. 61-81. 

 i North American Fauna, No. 3, p. 24 



