In China, Hume’s Leaf Warbler Phylloscopus humei mandellii (“Mandelli’s Leaf Warbler”) breeds eastern Qinghai to southeast Shanxi, Sichuan, and northern Yunnan. Non-breeding southeast Tibet, Indian Subcontinent, and Southeast Asia. Nominate in Xinjiang (Tianshan from Kashgar Prefecture east to Junggar Basin and Turpan Depression), non-breeding southern Tibet. HABITAT Breeds in coniferous, broadleaf, and mixed forests, also rhododendron scrub, to 3500 m (11,480 ft.); on passage and in winter in virtually any wooded or scrubby area, from sea level to 2100 m (6,890 ft.). ID & COMPARISON The Greater Ranges counterpart to Yellow-browed Warbler P. inornatus. In worn spring plumage, may be indistinguishable visually from Yellow-browed, but is generally greyer and less yellow and has less distinct eye-stripe, less mottled cheeks, and a nearly all-black bill and darker legs and shows only one prominent wingbar (on greater coverts). In fresh plumage, shows grey-green crown with faint yellowish-white median crown-stripe sometimes visible. Supercilium and ear coverts buffish, latter mottled olive-grey. Rest of upperparts olive-green, with no rump patch. Remiges and tail blackish-brown with green fringing; tertials dark grey with off-white fringing (showing less contrast than tertials of Yellow-browed). Wingbar on greater coverts buffish, not yellow, as in Yellow-browed; tips to median coverts usually faint and ill-defined, but may nonetheless be discernible as wingbar. Underparts dirtier white (greyish on throat and breast) with no hint of yellow on flanks and undertail coverts. Mandellii’s is brighter olive-green on upperparts and often shows yellow tinge to underparts, hence being more similar to Yellow-browed. VOICE Most reliable differentiator between Hume’s and Yellow-browed is voice. One call is a sparrow-like chirp, dsu-weet, often doubled and frequently repeated (also used as alternative song); another is softer and sweeter, tse-lu, second syllable lower pitched. Also rising call similar to Yellow-browed, but usually softer and lower pitched. Song an insect-like eeezzz, lasting about two seconds, descending in pitch and fading. — 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.