HYBRIDISM. 



In order to introduce the subject a brief synopsis must 

 be given of the suppositions advanced by some of our 

 most eminent ornithologists to account for this interesting 

 condition : Although Baird had apparently solved the ques- 

 tion satisfactorily away back in '58, other causes were sug- 

 gested or assigned from time to time, almost up to the present 

 date. Although suggesting that it might be due to environ- 

 ment or climatic influences, Maynard seemed convinced that it 

 was but the insensible gradation of one to the other, C. cafe)' 

 being but a more highly colored race ; Ridgway appeared to 

 have considered it the remnant of a generalized form from 

 which the eastern and western representatives had sprung ; an 

 opinion shared by Newton at the present time. Coues was un- 

 decided as to whether it was a hj^brid or transitional form. 

 Hargitt, though leaning toward the theory of hybridization, 

 suggests that it might be a sign of reversion to a remote 

 ancestral plumage. 



While hybridism has appeared the only solution to Ameri- 

 can ornithologists in recent years, it was not until 'i)2 that 

 seemingly overwhelming proof of the fact was presented by 

 Dr. Allen in a paper entitled The North American Species of the 

 Gemis Colaptcs ivith Special Reference to the Relationship of C. 

 anratus and C. cafer. He finds a complete blending "along 

 the line of juncture of the two .species from Southeastern Texas 

 northward along the western edge of the Plains into British 

 America, and then westw^ard in- British America to the Pacific 

 Coast in Southern Alaska." Mixed blood is of quite recent 

 introduction in California, apparently, probably within the 

 last thirt}^ years. It is now quite common, particularly in the 

 central and northern Pacific slope counties. While many are 

 migrants from the north a number are residents or breeders. 

 I have examined males taken in San Bernardino and Santa 

 Cruz — April 27, '83, and Sept. o, '95 — which undoubtedly 



