Vol. 5] 



Miller. — Pavo Calif ornicus. 



289 



addition of an American form it seems sufficient to indicate that 

 the present range is the focus of a contraction of the distribution 

 area. Whether or not the original center of distribution is 

 within the limits of the existing range is not at present to be 

 determined. 



It is impossible, also, to say what influences have so reduced 

 the range of the group when its close relatives, the quails, are 

 of such general distribution. The habits of the two existing 

 Pavos in their native haunts are those of jungle-dwelling fowl. 

 The unusual development and coloring of the plumage render 

 the good hiding places of a timbered country an effective factor 

 in preserving the species. We know nothing of the superficial 

 characters of the fossil species except by inference from the 

 tendency of existing Phasianines to unusual development of the 

 feathers, both as to form and color. The question naturally 

 arises whether P. calif ornicus, and such relatives as may have 

 existed with him in the Los Angeles region, suffered extinc- 

 tion because of inability to cope with the more or less treeless 

 condition that prevailed, or came to prevail, in that region. 

 Certainly cursorial power unimpeded by purely ornamental 

 structures would be needed to meet present conditions in that 

 locality. The Road Runner (Geococcyx calif ornicus) , a ground 

 dweller of such tail development as to earn the popular name 

 of ' ' California Peacock ' shows development of the rictrices 

 only, and unquestionably these are of tise in guiding the swift 

 movements of the bird in its efforts to escape its enemies, or in 

 pursuit of its active prey. Fleetness of foot and absence of 

 ornate coloring also characterize the coyote, the chief mammalian 

 enemy that such a bird would have had in this open country. 

 Possibly we may look upon physiographic conditions as the prime 

 factors that have cost our fauna this interesting group of birds. 



Issued August 11, 1909. 



Note. — Since the above description went to press, several additional per- 

 fect specimens of the tarso-metatarsus of P. calif ornicus have been obtained 

 at the type locality. These specimens agree exactly in specific characters 

 with the type specimen. 



