DISTRIBUTION OF YELLOW-RUMPED WARBLER 283 



Latham, and Pennant differs from the Yellow-rump of authors ; and have 

 accounted for the large number of polynomial Latin, French, and English 

 names that the same bird has received. The state of the case is nothing 

 unusual ; for though the number of names is perhaps in excess, yet this is 

 offset by the possibility of determining them all. The reader may imagine 

 how inextricable would have been the confusion had the bird been some 

 plainly-marked species closely reserablmg several others. 



WHAT little I have here to say of the Myrtle-bird relates 

 chiefly to its extensive dispersion in the West beyond 

 the recognized limits of the Eastern 

 Province, of which the bird has been 

 generally supposed characteristic. It 

 is not remarkable that it should have 

 been found in some cases on the 

 Pacific side, seeing that it extends 

 northwestward obliquely across Brit- 

 ish America into Alaska, where it 

 breeds, and whence some individuals ^iq. as.-Yeiiow-rumped warbier. 

 pass south, reaching Washington Territory and doubtless yet 

 other regions along the Pacific side. The westward trend of 

 the species in the United States may correspond nearly with 

 the oblique lay of the Coteau de Missouri in Dakota; thus 

 the birds are common at the proper season in the Red River 

 Valley, and thence in the same watershed nearly across Dakota, 

 along the parallel of 49° ; but directly west of this, in the Mis 

 souri watershed, and even in that of the Saskatchewan, they 

 are not known to occur ; and in the Rocky Mountains at 49°, 

 D. auduboni is the species, not D. coronata. 



The common and regular occurrence of the Yellow-rump in 

 the main chain of the Rocky Mountains is a fact of compara- 

 tively recent recognition, fully attested by such observers as 

 Trippe, Aiken, and Henshaw. Thus, the first named .of these 

 ornithologists speaks in the "Birds of the Northwest" of the 

 abundance of Myrtle-birds about Idaho and Colorado, where 

 they appear during the latter part of April, go as high as 8,500 or 

 9,000 feet, and disappear about the 10th of May, passing north. 

 Mr. Henshaw has recorded the capture of several specimens at 

 Denver, Colorado, where in early May the birds were noticed 

 with Audubon's Warblers, the two species associating so inti- 

 mately tbat they were sometimes heard singing in the same tree. 



I have in another bird-book noted the singular distribution 

 of this species according to season, without special reference 



