The Fox Sparrows 



lay mind. Yet to the student the outstanding joy of acquaintance with 

 the Fox Sparrow is the recognition of differences. Fox Sparrows from 

 Kadiak Island are different from Fox Sparrows in the Warner Mountains. 

 How? and why? Well, that would take a volume to tell; and the best 

 half of the facts would still have to be guessed at. All we can do is 

 to outline or summarize. 



The extremes of difference manifested within the ranks of the 

 "species" Passerella iliaca would undoubtedly be sufficient to justify 

 separation into distinct species, provided no intermediate specimens, 

 no "missing links," or intergrades, existed. But these do exist in un- 

 broken perfection, and we have, instead of, say, three separable species of 

 Fox Sparrows, a group of ten or a dozen (sixteen according to Mr. Swarth) 

 incipient species, each exhibiting certain tendencies or directions of 

 growth, and each entitled to some sort of distinctive recognition, yet 

 each surrounded by an aura of intergrades, an assemblage of "transitional 

 forms," every individual of which is just as well entitled to consideration, 

 to recognition, to description, as are those arbitrarily chosen by us for 

 distinctive attention. Hence, again, the species Passerella iliaca is one, 



Taken in Berkeley Photo by Amelia S. Allen 



MRS. ALLEN'S WINTER GUESTS 



YAKUTAT FOX SPARRO\v(S?). TWO PRINTS, POSSIBLY OF SAME BIRD, COMBINED 



and will continue to be such unless and until the Fox Sparrow population 

 of some intervening area drops out and so isolates a remoter group. 



The exceeding complexity of the problem which confronts the student 

 in the discussion of the monotypic genus Passerella may be summarized 



370 



