94 University of California Publications in Zoology [Vol.30 



Dwight's paper) accord with his statements, I believe, in every par- 

 ticular. Details here given are amplified in the belief that such studies 

 from all parts of the range of the willow ptarmigan are necessary to a 

 thorough understanding of geographical variation in this species. 



LIST OF THE NOETH AMEEICAN SUBSPECIES OF THE WILLOW 

 PTARMIGAN (LAGOPUS LAGOPUS) 



1. Lagopus lagopus alleni Stejneger. Allen Willow Ptarmigan. 



2. Lagopus lagopus ungavus Eiley. Ungava Willow Ptarmigan. 



3. Lagopus lagopus albus (Gmelin). Southern Willow Ptarmigan. 



4. Lagopus lagopus alascensis Swarth. Alaska Willow Ptarmigan. 



5. Lagopus lagopus alexandrae Grinnell. Alexander Willow Ptarmigan. 



Lagopus rupestris rupestris (Gmelin). Gray Eock Ptarmigan 



Thirteen specimens of rock ptarmigan (nos. 44712-44724) were 

 collected by myself in the Atlin region, including seven adult males, 

 two adult females, and four young birds. Brooks' Atlin series com- 

 prised about as many, similarly apportioned, and he later (September 

 11) collected at White Pass summit four additional specimens, two 

 adult females and male and female immature. 



The ptarmigans form a group of birds that offers many difflculties 

 to the systematist. The rapid and continuous changes of plumage 

 undergone by any one bird during the summer months, together with a 

 rather wide range of individual variation among specimens from any 

 given locality, are puzzling features in themselves, still further compli- 

 cated by other differences du» to sex and age. Then, ptarmigan, and 

 the rock" ptarmigan in particular, are not well represented in collec- 

 tions, inhabiting, as they do, relatively remote and inaccessible regions. 

 So, more often than not, when specimens are brought together from 

 different sections they prove to be not comparable, and deductions 

 then can only be made by inference. 



In a previous publication (Swarth, 1924, p. 333) I have commented 

 upon the appearance of a female rock ptarmigan from Nine-mile 

 Mountain, near Hazelton, British Columbia, a bird that differed appre- 

 ciably from the few Alaskan specimens available to me at that time. 

 The series we collected near Atlin, evidently in the same category as 

 the Nine-mile Mountain bird, seemed again so different from Alaskan 

 specimens as to justify more extensive comparisons. 



