1926] Swarth: Birds and Mammals from the Atlin Region 109 



on many occasions, and an old bird and one of its offspring were 

 secured, probably the first time that old and young of this form have 

 actually been collected. The young are distinctive and quite unlike 

 the young of cdurus, the other dark colored form of Buieo lorealis. 

 All this is corroborative of the theory that harlani is a "good" 

 subspecies, in the sense of being a geographic race. 



There is interesting evidence, of a negative sort, bearing upon the 

 migration route of the Harlan hawk, in the fact that in our series of 

 red-tails from the southwest, comprising about one hundred skins 

 from California, Nevada and Arizona, there is not one specimen 

 unequivocally of harlami. The only possible exception is an immature 

 female (Mus. Vert. Zool. no. 4094) taken at Julian, San Diego County, 

 July 27, 1908. This is a dark, blackish colored bird, like harlani in 

 shade of color, but it is peculiar in lacking any of the partly concealed 

 white spots and blotches that occur in that form. The uniformly black 

 color of this bird may well be explained on some ground other than 

 subspecific identity with harlani. 



The non-occurrence of harlani in so large a series of specimens from 

 the southwest is strongly suggestive of the migration route of this 

 bird extending southeast from the breeding ground, crossing the Rocky 

 Mountains in the far northern portion of that range. This is the 

 route that is known to be traversed by many species that spend the 

 summer in the extreme northwest, and what is known of the winter 

 habitat of the Harlan hawk is corroborative of such a theory. 



It is of interest to note that the red-tail {Buteo horeaiis alascensis 

 Grimiell) of the Sitkan district, Alaska, some one hundred miles to 

 the westward of the Atlin region, across the coast ranges, is of the 

 same general type of coloration as cailurus, to the southward, and shows 

 no approach toward the characters of harlami. 



In the light of all the foregoing facts, a revised statement of the 

 range of Buteo horeaiis harlani might be worded as follows: Breeds 

 in extreme northern British Columbia, east of the coast ranges, north 

 into the valley of the Yukon, and eastward for an undetermined dis- 

 tance. Migrates southward east of the Rocky Mountains, through the 

 Mississippi Valley to a winter home in the Gulf states. 



"While the bulk of evidence, as just given, is all corroborative of 

 this view, there are some opposing facts that should still be borne 

 in mind. The palest extreme of the red-tailed hawk, B-wteo horeaiis 

 krideri, has been taken in the same general region, at Eagle, Alaska, in 

 winter (Bailey, 1916, p. 321), and on the Stikine River, breeding 



