AUDUBON WABBLEB 



527 



distinctive enough in character to serve as a means of reco^ition once 

 it has been learned by the observer. In March or April, before the birds 

 depart from the lowlands, the males begin to sing, and after the birds 

 arrive on their nesting grounds the full songs are to be heard regularly 

 and frequently through May and June and, especially at the higher 

 altitudes, even well into July. 



The song resembles most nearly that of the Hermit Warbler, but is 

 more mellow and tinkling, and lacks the burred or *z' tones of the latter 's 

 utterance. One phrasing of the Audubon's songs goes si-wi, si-wi, si-wi, 

 sissle, sissle, see-see; another turly, urly, urly, urly, urly, i-cl. These are 

 given much as if the syllables were spoken rapidly and in a whispering 

 voice. 



Fig. 57. Tails of (a) Alaska Myrtle Warbler and (&) Audubon Warbler; natural 

 size. Note that in the former the white (clear) areas are present on only six feathers, 

 whereas in the latter species ten feathers bear white. This character, under favorable 

 conditions, may be used in field identification. 



During the summer season the Audubon Warbler keeps mainly to 

 coniferous trees, foraging from 10 to 50 feet or more above the ground. 

 In the Transition Zone and part of the Canadian Zone it shares this 

 habitat with the Hermit Warbler, but at higher altitudes it is the only 

 warbler present in the evergreen forests. In this same niche its nesting 

 is carried on. After the breeding season this restriction is broken and 

 the Audubons range widely here and there, wherever food offers. In the 

 dry days of autumn when the wind is shaking down the dead leaves of 

 the deciduous trees the birds spend their time about such trees seeking 

 the flying and other insects then available. When they move into the foot- 

 hills and valleys for the winter they take to a variety of situations, hunting 

 often in the live oaks, again in shrubbery or in low chaparral, and not 

 infrequently alighting on the grass or ground in pursuit of some terrestrial 

 insect. Few other insectivorous birds show such seasonal diversity in 

 forage grounds. 



