524 ANIMAL LIFE IN THE YO SEMITE 



The Alaska Myrtle Warbler is occasionally to be detected in flocks of 

 the more common Audubon Warbler. In voice, habits, and general appear- 

 ance it resembles closely the latter species. Discriminating observers will 

 be able to note the lesser amount of white on the tail and the regularly 

 white chin. This warbler has thus far been recorded from a single locality 

 in the Yosemite region, at Dudley on Smith Creek, six miles east of Coulter- 

 ville. The records listed above were all made at this station by Mr. Donald 

 D. McLean. Continued observations at other localities on the west slope 

 of the mountains would probably show the species to be of regular occur- 

 rence, though in limited numbers, during the winter months, perhaps in 

 a ratio of not more than one Myrtle Warbler to a hundred or so of 

 Audubon Warblers. 



Audubon Warbler. Dendroica auduboni auduboni (Townsend) 



Field characters. — Size two-thirds that of Junco. Rump always yellow (except in 

 young newly out of nest), and tail large-appearing and always with a wide bar of white 

 across it near end (fig. 57b). Chin usually distinctly yellow. Adult male in summer: 

 Top of head, chin, rump, and patch on each side of breast yellow; breast black; upper 

 surface bluish gray streaked with black. (See pi. 9e.) Adult female in summer: Top 

 of head, chin, and rump yellow; breast mottled with gray and black; upper surface 

 bluish gray. Adults and immatures in winter : More or less brownish both above and 

 below; little or no black on breast; chin usually (but not always) distinctly yellow, 

 though rump always so. All movements quick and nervous; often flies out from foliage 

 of tree in semicircular course. Voice: Song of male a series of mellow notes, run 

 together rapidly, not loud, and of tinkling quality; call note of both sexes a sharp tsip. 



Occurrence. — In summer common visitant to Transition, Canadian, and Hudsoniau 

 zones on both slopes of Sierra Nevada (most plentiful in Canadian) ; recorded from 

 3 miles east of Coulterville eastward clear across the mountains to Mono Lake Post 

 Office. Eemains in Transition through October. Keeps chiefly to coniferous trees, 

 foraging 10 to 50 feet or higher above ground, and nests in same situations. In pairs 

 or solitary. In winter common visitant to Lower and Upper Sonoran zones on west side 

 of mountains, as at Snelling, Lagrange, Pleasant Valley, and El Portal. At this season, 

 forages extensively in outer parts of broad-leafed trees. Solitary, or in scattering 

 companies, often with birds of other species. 



The Audubon Warbler is the most widely distributed and the most 

 abundant of all the species of wood warblers found in the Yosemite region. 

 It occurs in numbers throughout the main forested districts of the moun- 

 tains during the summer season, and it frequents the deciduous trees and 

 brush of the foothill and valley country in the winter time. 



Altitudinally its summer range extends from the beginning of the 

 Transition Zone yellow pines on the west slope, at 3300 to 3500 feet, up 

 through the lodgepole pines and other conifers of the Canadian and Hud- 

 sonian zones to the upper limit of unstunted trees at 10,000 feet or a 

 little higher. It distribution is uninterrupted from near El Portal and 

 the ridge of hills above Coulterville eastwardly across the moimtains, 

 through the Tioga and Mono passes, to Williams Butte and Mono Lake. 



