Yellow-bellied Warbler Abroscopus superciliaris Scientific name definitions

9 cm; 6–7 g. A small, rather slim, almost featureless yellow-and-olive warbler with relatively large bill; short undertail-coverts and narrow tail (usually kept closed) combine to give rear end a distinctive appearance when bird viewed from below. Nominate race has forehead, crown and nape dark grey, off-white supercilium extending well behind eye, highlighted by dark lores and grey or brownish-grey ear-coverts (darker around eye); upperparts olive-green, weak yellowish wash on rump and uppertail-coverts; wings and tail brownish, feathers broadly edged with olive-green; chin, throat and chest off-white, remainder of underparts, including underwing-coverts, lemon-yellow; iris dark brown, inconspicuous thin whitish broken eyering; bill dark brown, becoming dull pinkish at base of lower mandible; legs rather pale pinkish-brown or pale pinkish. Sexes similar. Juvenile is duller than adult, with duller darker olive upperparts, lighter yellow underparts. Races differ mainly in colour saturation, especially crown and nape colour and degree of contrast between nape and mantle, extent of white on breast, and intensity of yellowish wash on rump: flaviventris has nape olive-grey and merging with mantle colour, whitish below confined to chin and throat, with chest yellow; drasticus has brownish-grey crown contrasting with olive mantle, strong yellow wash on rump and uppertail-coverts, deep golden-yellow underparts; smythiesi has olive-green crown, paler yellow wash on rump, and yellow on underparts shading to whitish on central belly; <em>euthymus</em> is dark, has almost sooty-grey crown contrasting with dark olive upperparts, quite defined narrow band of yellowish across rump, deep golden-yellow underparts (including chest); bambusarum is almost as dark above as previous, but has paler grey crown, lemon-yellow underparts, white of throat extending to chest; sakaiorum is similar to last, but white of throat extending to breast and belly centre; papilio, vordermani and <em>schwaneri</em> are all relatively dark, having especially dark grey crown and ear-coverts, making whitish supercilium more obvious.

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.

Recently recorded in SW Guangxi (race unknown, but presumably either nominate or euthymus) (2 Jiang, A., F. Zhou, and N. Liu (2014). Significant recent ornithological records from the limestone area of south-west Guangxi, south China, 2004–2012. Forktail 30:122–129. Close ).

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SUBSPECIES

Abroscopus superciliaris flaviventris Scientific name definitions

Distribution

Nepal, NE India (Sikkim, N West Bengal, Arunachal Pradesh, Meghalaya, Nagaland, Manipur), Bhutan, E Bangladesh and W Myanmar.

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SUBSPECIES

Abroscopus superciliaris superciliaris Scientific name definitions

Distribution

E and S Myanmar, S China (S Yunnan and SW Guangxi), and N and SW Thailand E to C Laos.

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SUBSPECIES

Abroscopus superciliaris drasticus Scientific name definitions

Distribution

NE India (Assam) and N Myanmar.

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SUBSPECIES

Abroscopus superciliaris smythiesi Scientific name definitions

Distribution

C Myanmar.

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SUBSPECIES

Abroscopus superciliaris euthymus Scientific name definitions

Distribution

Vietnam.

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SUBSPECIES

Abroscopus superciliaris bambusarum Scientific name definitions

Distribution

N peninsular Thailand.

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SUBSPECIES

Abroscopus superciliaris sakaiorum Scientific name definitions

Distribution

S peninsular Thailand and Peninsular Malaysia.

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SUBSPECIES

Abroscopus superciliaris papilio Scientific name definitions

Distribution

Sumatra.

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SUBSPECIES

Abroscopus superciliaris schwaneri Scientific name definitions

Distribution

Borneo.

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SUBSPECIES

Abroscopus superciliaris vordermani Scientific name definitions

Distribution

Java.

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.

Undergrowth of evergreen forest, especially bamboos by streams in low hills, mountain foothills and adjacent plains; less frequent in secondary scrub. Lowlands to 1525 m, and reported to 2200 m in Bhutan and 2285 m in Nepal.

Basically resident; distinct shift to lower elevations for winter, when may be encountered by forest streams in plains in areas where not known to breed. However, the record of an individual at Satkosia Tiger Reserve, Odisha (E India) on 3 May 2009, may point to still unknown wintering areas further south (3 Singh, D.K. and Panda, A.C. (2014). Sighting of Yellow-bellied Warbler Abroscopus superciliaris in Odisha, lndia. Indian Birds. 9(5-6): 167. Close ).

Food almost entirely tiny invertebrates; items recorded include tiny spiders (Araneae), small dipteran flies including mosquitoes (Culicidae), also eggs of butterflies (Lepidoptera). Forages chiefly in understorey , but will freely move into upper canopy and among hanging creepers. Gleans food items from foliage; small insects also taken on the wing during short flycatching sallies. Outside breeding season often forms small parties; sometimes accompanies mixed-species flocks, but seems less prone to do so than are its congeners.

Song a somewhat halting delivery of c. 6 high-pitched piercing whistled notes, almost of tinkling quality, somewhat tremulous in central part of phrase, and rising towards end, as e.g. rapid “dee-dee-dir-rit-tit-deweet”; phrase repeated three or four times, each time higher in pitch than previous phrase. Also reported is a continuous subdued twittering, probably a form of contact note.

Season early Apr to Jun in NE India, from latter part of Mar in N Borneo. Nest constructed by both sexes, a compact cup of moss, fibres and rootlets placed upon small foundation of bamboo leaves, located within 2 m of ground and usually in hollow among mass of bamboo stems, or in split or broken bamboo, close to stream. Clutch 2–5 eggs; incubation by both sexes, period not documented; no information on nestling period. Nests parasitized by Common Cuckoo (Cuculus canorus).

Not globally threatened (Least Concern). In Nepal, relatively common only in extreme SE; several reports from C Nepal (W to Pokhara and Chitwan), where possibly only an uncommon non-breeding visitor. In India, locally common in E Himalayan foothills of Sikkim and seems to be not uncommon in lower hills in Arunachal Pradesh, Nagaland and Manipur. In Bhutan, quite frequently encountered in S parts of the Dzongkhags of Geylegphug, Mongar, Shemgang and Samdrup Jongkhar. Scarce in Bangladesh, where restricted to E of country. Common in its rather limited range in S China, and common also in Vietnam (S to C Annam) and adjacent parts of Laos. Considered to be common and widespread in Myanmar, Thailand and Peninsular Malaysia, and seems to be locally quite numerous in Borneo, Sumatra and Java. This species’ relatively wide distribution and its tolerance of patchy forest should ensure its survival in the immediate future.