WOOD WARBLERS 411 



zona between 9000 and 10,000 feet, the male following the female 

 about while she collected material for the nest, uttering at times ' a 

 liquid quirt, quirt, quirt, in a descending scale.' 



Subgenus Dendroica. 



652. Dendroica sestiva (Gmel.). YELLOW WARBLER. 



Adult male. Under parts yellow ; breast and belly streaked with rufous ; 

 forehead bright yellow, front of crown often tinged with 

 orange ; hind neck and rest of upper parts yellowish 

 green, brightest on rump ; wing edgings yellow ; inner 

 webs of tail feathers, except middle pair, light yellow. 

 Adult female and male in first autumn : upper parts plain 

 yellowish green, usually darker than in male, lighter on 

 forehead and rump ; under parts paler and duller, visually 

 unstreaked. Young female in first autumn : like adult female, but duller 

 olive green above, olive whitish slightly tinged with yellow below ; under 

 tail coverts pale yellow. Male : length (skins) 3.94-4.92, wing 2.36-2.80, 

 tail 1.05-2.09, bill .39-.43. Female: length (skins) 4.02-4.57, wing 2.24- 

 2.68, tail 1.54-1.77, bill .39-.43. 



Remarks. The yellow on the inner webs of the tail feathers, together 

 with the general yellow coloration, are enough to distinguish the cestiva 

 group in all ages and sexes. 



Distribution. North America, except Alaska and southwestern United 

 States ; mig-rates to Central America and northern South America. Breeds 

 nearly throughout its North American range. 



Nest. Compact and cup-shaped, made largely of gray plant fibers, 

 lined with down and feathers ; placed in bushes or trees. Eggs : 2 to 6, 

 greenish, spotted usually around larger end with brown, black, and lilac 



grav. 



Food. Insects. 



The yellow warblers are birds of the chaparral, of willows, and 

 thickets along streams in uninhabited regions, and of parks and 

 gardens where the gods provide. When seen in the chaparral thick- 

 ets the glimpse of yellow tail patches is enough to identify them as 

 they disappear, but in towns where they are tame the bricky streak- 

 ing of the breast can be seen as they stand on a flowering bush and 

 lift their heads to sing. They have so much singing to do and so 

 many insects to catch that it keeps them busy. Their song is loud 

 and cheery and they have the fine chip of their family. In their 

 manner of life they belong to the quiet part of the warbler tribe, 

 hunting usually in a leisurely way as if they knew that their song 

 was needed to add the real summer feeling to the blooming shrubs. 



652a. D. a. sonorana Brewst. SONORA YELLOW WARBLER. 



Like a?stiva, but imich paler ; adult male lighter, more yellowish olive 

 green above, back often streaked with brown, crown usually clear yellow ; 

 under parts lighter yellow than in estiva; chest and sides more narrowly 

 streaked ; adult female conspicuously paler than in estiva, upper parts often 

 largely pale grayish ; under parts usually pale buffy yellow. Male : length 

 (skins) 4.21-4.76, wing 2.32-2.60, tail' 1.77-2.20. bill .39-43. Female: 

 length (skins) 4.33-4.57, wing 2.24-2.40. tail 1.65-1.77. bill .39. 



