48 



BULLETIN 



UNITED STATES NATIONAL MUSEUM. 



very closely resembling the adult male of ChordeUes virginianus 

 henryi; or even to a lighter brown, very much mottled (No. 6819, 

 J. Grinnell, Bluff Lake, San Bernardino Mountains, California, 

 July 22, 1905), like the male of ChordeUes mrginianus howelli. 



As in ChordeUes virginianus virginianus^ there is little or no geo- 

 graphical variation in this race. Breeding birds from southern Cali- 

 fornia seem to be practically identical in both color and size with 

 those from northern California, Idaho, western Montana, and other 

 parts of the breeding range. Breeding birds from Nevada seem to 

 be all ChordeUes v. hesperis, and identical with California specimens. 

 One breeding example from the Hood River, Oregon (No. 156571, 

 U.S.N.M., June 21, 1897), looks like ChordeUes virginianus virgini- 

 anus; but others from North Dalles and Fort Steilacoom, Washing- 

 ton, from Heppner and the John Day River, Oregon, are surely Chor- 

 deUes V. hesperis; and while all the breeding birds available from 

 Oregon and southern Washington are somewhat intermediate between 

 C. V. virginianus and C. v. hesperis^ they are much nearer the lat- 

 ter. A single specimen from the Milk River, at latitude 49°, Mon- 

 tana (No. 67646, U.S.N.M., July 24, 1874), others from the Sun 

 River and elsewhere in western and central Montana, as well as 

 southern Idaho, are practically indistinguishable from California 

 examples of ChordeUes virginianus hesperis. One half-grown bird 

 in Juvenal plumage from the Upper Geyser Basin, Yellowstone Na- 

 tional Park, northwestern Wyoming (No. 62256, U.S.N.M., Aug. 20, 

 1872), is apparently the present form, being much too grayish for 

 ChordeUes virginianus howelli^ and too dark for ChordeUes vir- 

 ginianus sennetti. Breeding birds from Trail, southeastern British 

 Columbia, close to the boundary of the State of Washington, verge 

 toward ChordeUes virginianus virginianus^ but are decidedly nearer 

 ChordeUes v. hesperis. A series of breeding specimens from Maple 

 Creek, southwestern Saskatchewan, and two individuals from Indian 

 Head, Saskatchewan, incline somewhat toward ChordeUes v. sen- 

 netti, but are clearly the present form. Average measurements of 

 breeding specimens from different parts of the range compare as 

 follows : 



1 See p. 57. 



