98 Figgins, Races of Branta canadensis. [j^. 



canadensis, where a suggestion of such markings occasionally 

 occurs." 



This would appear to effectually dispose of occidentalis as a sub- 

 specific variety. Swarth's contention for a difference in size when 

 compared with canadensis is not convincing when he and Baird 

 himself, evidently entertained a doubt as to whether the type speci- 

 men is really distinct. The present writer interprets Swarth's 

 description of occidentalis as an attempt to justify the continuance 

 of this variation as a subspecies by crediting it as being a more or 

 less resident form inhabiting the Pacific coast from Port Townsend 

 to Prince William Sound, but admits the birds of " extremely dark 

 coloration" are "closer to the range of minima and it is fair to 

 believe that these specimens illustrate a step in the gradual transi- 

 tion between the two forms, which probably occurs." 



He has shown that the white collar and black stripe on the 

 throat are not diagnostic characters, — being " no more consis- 

 tently present in the race occidentalis than they are in true cana- 

 densis." The statement that "Of the Alaskan series the Prince 

 William Sound birds are smaller and darker than those of the Sitkan 

 district . . . . " points rather conclusively to gradation through 

 hybridism. It is doubtful if a large number of ornithologists will 

 agree that an unsupported proposal of an unusual migration move- 

 ment warrants assigning such specimens to a subspecific form that 

 makes a second description necessary as a means of coordinating 

 it with a theory. 



The literature dealing with the distribution, of the genus Branta 

 fails to take into account the region lying between Prince William 

 Sound and Bering Sea. This comprises the Kenai Peninsula, 

 Kachamak Bay, Cook Inlet and the great alluvial valley to the 

 northeast, as well as the southern slope of the Alaskan mountains 

 from Mt. McKinley to the Alaskan peninsula. A large part of 

 this territory is ideal breeding ground and to the present writer's 

 personal knowledge, examples of Branta are found there in con- 

 siderable numbers during July, August and September, although 

 no specimens were taken. There are no land barriers that would 

 prohibit these birds crossing from Prince William Sound to Cook 

 Inlet and hence it is not unreasonable to expect that minima and 

 canadensis and Baird's so-called occidentalis interbreed and hence 

 the "variations" and specimens that intergrade "inextricably." 



