The largest wood warbler: robust build, large bill with strongly curved culmen, long tail, and distinctive plumage distinguish this species from all other wood-warblers and similarly colored songbirds. Upper parts olive-green to grayish-olive; chin, throat, and breast lemon-yellow (sometimes tinged with orange), contrasting with mainly white belly and under tail-coverts. Face grayish with black lores, white supercillium, and white eye-crescent on lower eye-lid. Sexes very similar, but during breeding season, female has grayish lores, gray lower mandible, and pink mouth-lining, in contrast to male's black. Little seasonal change although upperparts more brownish, yellow underparts more olive, and flanks more buffy or brownish, and bill more brownish in winter (Eckerle and Thompson 2001).
For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.
Western Hemisphere Range
Found in low, dense vegetation without a closed tree canopy, including shrubby habitat along stream, swamp, and pond margins; forest edges, regenerating burned-over forest, and logged areas; and fencerows and upland thickets of recently abandoned farmland (Eckerle and Thompson 2001).
Adults feed on small invertebrates (mainly insects and spiders), fruit and berries when available (Eckerle and Thompson 2001).
Nests usually placed near ground in dense thickets and shrubs that provide concealment. Eggs are ovate to subelliptical in shape; color white or creamy-white with reddish brown, chestnut red, brown, and paler gray or purple speckles. Clutch size varies form 3 to 5 eggs (Eckerle and Thompson 2001). Eggs have been observed June 11 and 19.