54 PACIFIC COAST AVIFAUNA. [No. 4 



.ai'ether with D. hnciiscndi, D. occidcntalis, Virco s. cassini, and others 

 passing- through here at the same time. 



Dendroica auduboni (Townsend). Audubon Warbler. 



I was surprised at not finding this species in the mountains during' 

 the winter months, but it seems to occur in the Huachucas only as a 

 migrant. A single bird was seen near the base of the mountains on 

 March 6th, but he was much in advance of the rest of his tribe, for no' 

 more were seen until March 24th ; after which they steadily increased in 

 numbers until the end of April. A great many were seen in the pines on 

 the top of the mountain on May 11, 1903, and they left rather abruptly 

 about a week later. Though distributed over all parts of the mountains, 

 they were at all times more abundant in the higher pine region, than 

 elsewhere; and on April 24, 1903, I found them particularly numerous 

 along the divide of the mountains, evidently migrating. They could 

 hardly be said to be in flocks on this occasion, for along- the ridge, which 

 runs almost due north and south, there was for several miles a continu- 

 ous stream of Audubon Warblers travelling rapidly from tree to tree, 

 always moving in a northerly direction ; sometimes a dozen or more in- 

 one pine, and sometimes only two or three, but never stopping long and 

 all moving in the same direction. Almost all that were seen on this 

 occasion were high phmiaged males, hardly half a dozen females being 

 observed for the day. 



Dendroica auduboni nigrifrons (Brewster). Black-fronted Warbler. 



This, the only form of andnboin that breeds in the Huachucas, oc- 

 curs during the summer months, though in rather limited numbers, in 

 the higher pine regions from 8500 feet upwards. On one occasion, April 

 5, 1903, I secured a male nigrifrons from a flock of auduboni feeding in 

 some live-oaks near the mouth of one of the canyons at an altitude of 

 about 4500 feet, but this is the only time that I have seen it below the 

 altitude given above ; and it is also exceptional in the early date of its 

 arrival. No more were seen until the second week in May, which seems 

 nearer the usual time of arrival, for in 1902, the first seen was on May 

 9th. A young bird just from the nest was secured on July i, 1902, and 

 another about the same age was taken on July 13th. A young male 

 taken August 19th. which has discarded the streaked juvenile, for the 

 first winter plumage, is practically indistinguishable from specimens 

 of auduboni at the same stage, being perhaps a shade darker throughout. 

 In two adult males, taken August 26th and August 30th, respectively, 

 which have practically completed the postnuptual moult, the black of 

 the under parts is quite as extensive as in spring birds, but obscured by 

 gray tips to the feathers. In one the feathers of the back are much as 

 in spring birds, though with rather broader gray edgings and overcast 

 with a faint wash of brown ; while the white patch formed by the edgings 

 and tips of the middle and greater wing coverts is nearly perfect. In the 

 other, the plumage of the back is overcast with brown to such an extent 

 that hardly a trace of the dark centers of the feathers is discernable, 

 while the white wing patch is heavily washed with the same. 



Several specimens were taken intermediate in their characteristics 

 between auduboni and nigrifrons: some, of the size of the latter, though 

 in color but little darker than auduboni, while some show every grada- 

 tion of color between the two extremes. 



In the darkest specimens of Jiigrifrons the black of the under parts 

 extends from the yellow throat patch to the flanks uninterruptedly, even 



