Black-browed Bushtit Aegithalos bonvaloti is high-altitude counterpart to Black-throated Bushtit A. concinnus; also closely related to Rufous-fronted Bushtit A. iouschistos. Two ssp., both in China: obscuratus Qionglai Mountains in west-central Sichuan and bonvaloti from western Sichuan south of obscuratus to southeast Tibet (where range abuts Rufous-fronted) and western Yunnan and east to western Guizhou. Breeds to 4000 m (13,120 ft.), lower in winter. ID & COMPARISON Adult has broad black headbands from bill to sides of nape, encompassing eye. Narrow median crown-stripe white in front, buff behind. Mantle, wings, and tail mainly grey; sides of tail white. White submoustachial stripe. Chin and bib diffusely black, demarcated by black lateral throat stripes. Rusty cheeks and neckband divided by greyish-white area reaching from below bib to nape sides. Broad breast band and flanks orange-brown; belly whitish. Race obscuratus duller and browner. Juveniles lack bib and are paler below and have a narrow black breast band. Underparts of Rufous-fronted uniform cinnamon-brown, leaving whitish bib as bird’s palest area (except sides of tail); extensive cheeks, median crown-stripe and submoustachial stripe rufous-buff. Black-throated Bushtit has wider, brighter, more orange-brown median crown-stripe and a much more clearly demarcated throat patch. Sooty Bushtit A. fuliginosus and Black-throated Parrotbill lack black headband. BARE PARTS Bill tiny, black; feet brownish-orange; iris pale yellow. VOICE Typical of genus; foraging groups emit constant chirrs and thin tsips. — Craig Brelsford
Daniel Bengtsson served as chief ornithological consultant for Craig Brelsford’s Photographic Field Guide to the Birds of China, from which this species description is drawn.