Greenish Warbler Phylloscopus trochiloides breeds northeast Europe to central Siberia plus Himalayas and Tibetan Plateau. In China, viridanus breeds western Xinjiang; trochiloides southeast Tibet, southern Sichuan, and northwest Yunnan, wintering in Yunnan; and obscuratus eastern Qinghai to southern Gansu and Sichuan, wintering south China from Yunnan to Hainan. HABITAT & BEHAVIOR Breeds in deciduous and coniferous forests and subalpine rhododendron shrubberies, to 4500 m (14,760 ft.) . Non-breeding in variety of well-wooded lowland habitats. Alone or in pairs in breeding season; non-breeders often in mixed flocks. Active at all levels of forest, from ground and low bushes to canopy. ID & COMPARISON Medium-sized, greenish-grey leaf warbler with one or (rarely) two pale, fine wingbars. Long, distinct, yellowish-white supercilia usually join on forehead. No crown stripe. Off-white underparts with yellow tinge to throat and upper breast. Similar to Large-billed Leaf Warbler P. magnirostris. Best told from Two-barred Warbler P. plumbeitarsus by finer, shorter wingbars (not reaching scapulars), more diffuse than the more clearly demarcated wingbars of Two-barred; also, Two-barred usually shows two wingbars, Greenish usually one. On average, Two-barred is slightly greener above and cleaner white below, has more obvious yellow tone on supercilium and sides of head and throat, and has a slightly thicker bill and a darker and more prominent eye-stripe (reaching bill). Greenish Warbler has a shorter supercilium behind the eye, but it reaches forehead, and loral stripe does not reach base of bill (may form just a spot in front of eye). Common Chiffchaff P. collybita lacks (or has indistinct buff) wingbar, has less distinct facial pattern, and is greyer on head and mantle. Nominate slightly darker, more often shows a second wingbar, and has darker bill than viridanus. BARE PARTS Bill fine, dark brown above, orange below, with diffuse dark tip; feet brownish to brownish-pink. VOICE Calls throughout year, a sharp, two-note burst, second note higher, reminiscent of White Wagtail or Eurasian Tree Sparrow. Song of viridanus a rapid, melodious warble 3-5 seconds long. Song of trochiloides simpler and less warbling, mainly switching between two or three pitches. Call of Two-barred often appears even more distinctly two-noted, sometimes even trisyllabic; song generally softer, less staccato. — 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.