Chestnut-crowned Warbler Phylloscopus castaniceps Scientific name definitions

9–10·5 cm; 4–6 g. Tiny, acrobatic warbler with prominent pale wingbars. Nominate race has crown and supercilium rufous-chestnut, dark lateral crown-stripe blackening and broadening towards nape; some broken whitish streaking often visible at nape side, otherwise nape, head side, mantle and scapulars grey, back and wings yellowish olive, two yellow bars formed by tips of median and greater wing-coverts; clear yellow rump and uppertail-coverts; tail feathers ashy brown, fringed yellowish olive, white inner webs of outermost two rectrices; throat and breast to uppermost belly grey, rest of underparts lemon-yellow, whitish at centre, underwing-coverts pale yellow; iris blackish brown, clear whitish narrow eyering; upper mandible dark brown, lower mandible yellowish flesh; legs fleshy yellow, soles almost white. Sexes alike. Juvenile has drab grey-brown crown for a short while only; otherwise much as adult but duller overall, with paler yellow underparts. Race <em>sinensis</em> has lighter chestnut crown and darker green upperparts than nominate, more extensive yellow over lower underparts; laurentei has greenish wash on both rump and underparts, whitish on upper belly; <em>collinsi</em> has mantle and back grey, yellow of rump and underparts washed green, yellow below confined to flanks and undertail-coverts; stresemanni is similar to nominate but has richer chestnut crown, rather more extensive grey on mantle, and yellow of rump less bright and reduced in extent; annamensis differs from previous in having richer chestnut head, green mantle, less extensive yellow on rump, darker grey breast well demarcated from yellow belly and lower underparts; youngi lacks yellow on rump, which slightly paler grey than rest of upperparts, has lower underparts extensively whitish, with yellow chiefly on flanks; butleri differs from last in darker chestnut crown (lateral stripe less distinct), generally darker upperparts with greener rump, slightly more extensive yellow below; muelleri has yellow rump and uppertail-coverts more like nominate, but lower underparts white with yellow confined to flanks.

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Tiny invertebrates, chiefly insects. Extremely active; forages amid outer foliage of upper canopy, quickly hovers, then tumbles down to lower levels, accompanied by wing-flicking and tail-flashing. Food items obtained mostly by gleaning. Associates with mixed-species parties outside breeding season.

Song (only recently described) of an ethereal quality, very thin and very high-pitched, a series of 5–7 upwardly inflected notes, e.g. “see see see-see-see-see-see”. Calls include repeated subdued “chik” and doubled “chee-cheee”.

Feb–Jul, generally associated with start of wet season; chiefly Apr–Jun in Indian Himalayas. Nest built by both sexes, a compactly woven oval ball of green moss , with dense lining of felted moss and tiny moss threads; well concealed on ground, hidden by overhanging mosses and creepers, often below bushes or in hollow at foot of tree, on bank or steep slope. Clutch 3–5 eggs; incubation by both sexes, duration not documented; no information on nestling period. Nests parasitized by Himalayan Cuckoo (Cuculus saturatus) and Asian Emerald Cuckoo (Chrysococcyx maculatus).