136 University of California Publications in Zoology [Vou 30 



Certain Alaskan skins are paler colored than any eastern birds, and 

 some have decidedly more extensive white markings (as on the lateral 

 rectrices) than most eastern skins. An exceptional British Columbian 

 specimen has the outer rectrices entirely white. There are Alaskan 

 birds, though, that lie well within the range of variation of eastern 

 birds, and there are one or two eastern birds with white markings on 

 the tail feathers nearly as extensive as in any western ones. 



There are a number of winter birds in this series from points lying 

 between the Great Lakes and the Rocky Mountains, and nearly all of 

 these I am unable to allocate to an eastern or a western race with anj"^ 

 degree of assurance. Thus, while recognizing in the northern shrike 

 a tendency toward development of the characters ascribed to invictus 

 in the western part of its habitat, it seems to me so impossible to define 

 the boundary between an eastern and a western race, or to identify 

 most winter birds taken south of the breeding range, that I am 

 disinclined to use different names for the variations exhibited. 



Vireosylva gilva swainsonii (Baird). Western Warbling Vireo 



A rare species, here probably at the extreme northern limit of its 

 range. First seen June 8, and from then on, at this one place, a vireo 

 could be seen or heard singing at almost any time during the next 

 few weeks. The indications were that a pair was nesting there- 

 about. The only other occasion on which the species was seen was on 

 August 17, when one bird was collected by Brooks. 



Vermivora celata celata,(Say). Orange-crowned Warbler 

 Migrating, not uncommonly, about Atlin, during August. Three 

 specimens were collected (nos. 44901-44903), two females taken 

 August 13, and one male on August 17, all immatures in first winter 

 plumage. Others of this subspecies, easily recognized as a rule by the 

 gray head, were seen until August 31. 



Vermivora celata orestera Oberholser 



Eocky Mountain Orange-crowned Warbler 



An "orange-crowned warbler," apparently of this subspecies, was 



seen at Carcross, May 24. Small numbers were migrating through 



the Atlin region during the last week in May and first week in June, 



and a few pairs bred in the lowlands thereabout, where they were seen 



