Aberrant Bush Warbler - BirdForum Opus

by range, the image should show a bird of subspecies intricatus
Photo © by China Guy
Sichuan, China, January 2009

Horornis flavolivaceus

Identification

12–13·5 cm (4¾-5¼ in). A medium sized bush-warbler with short, rounded wings and average tail length, perhaps the most phylloscopus like shape wise in the region.

Yellowish olive-green upperparts
Pale yellowish supercilium
Narrow whitish eyering
Dark eyestripe
Buffish or ollive-yellow underparts, darker olive on breast and flanks (variable)
Dark eye
Dark horn-brown bill, pale pink base of lower mandible
Yellow to dusky pinkish-brown legs

Sexes similar. Juveniles are similar to adults but have uniform buffish-yellow underparts.

Variations

alexandri with olive-brown upperparts but darker olive-buff underparts than nominate and with buffish breast and flanks
weberi with strong rufescent-brown wash above and below, longer tail and ochre-brown breastband and flanks
intricata is similar to weberi but paler and less yellow on underparts
obita is similar to intricata but smaller and with brighter olive upperparts, washed pale yellow underparts and rufous-ochre flanks

Subspecies oreophilus, part of the former Sunda Bush Warbler
Photo © by Jason Bugay Reyes
Kinabalu National Park, Sabah, Malaysia, Borneo, March 2008

Similar species

Greener (not rufous) upperpart than Yellowish-bellied Bush Warbler without rufous wingpanel and yellowish (not grey) throat and breast. Differs from Brownish-flanked Bush Warbler in yellower supercilium obvious before eye, greener upperparts having the same colour like crown and yellowish underparts tinged olive on breast and flanks.

Distribution

India and China east to Vietnam and Thailand as well as Greater Sundas and Lesser Sundas.
Common to fairly common in parts of its range.

Taxonomy

Formerly placed in genus Cettia.

The first eight subspecies were formerly considered a separate species, the Sunda Bush Warbler.

Subspecies

Clements recognizes these subspecies[1]:

H. f. sepiarius:

Mountains of northern Sumatra

H. f. flaviventris:

Mountains of central and southern Sumatra

H. f. vulcanius:

Java, Bali, Lombok and Sumbawa

H. f. kolichisi:

Alor (Lesser Sundas)

H. f. oreophilus:

Northern Borneo (Mount Kinabalu)

H. f. banksi:

Mountains of northern Borneo (Sabah and Sarawak)

H. f. palawanus:

Mountains of Palawan (south-western Philippines)

H. f. everetti:

Timor (eastern Lesser Sundas)

H. f. flavolivaceus :

Himalayas of Garhwal to Nepal, Arunachal Pradesh and southeastern Tibet

H. f. stresemanni:

North-eastern India (Garo and Khasi hills of Assam)

H. f. weberi:

extreme northeastern India (Nagaland, Manipur, and eastern Mizoram) and adjacent western Myanmar south to the Chin Hills

H. f. intricatus:

Northern and eastern Myanmar and south-western China (southern Shanxi, eastern Sichuan)

H. f. oblitus:

Northern Laos and northern Vietnam

Former subspecies alexandri is considered a synonym of weberi.

Habitat

Found in bushes, tall grass clumps, ferns, dense bamboo thickets and scrub undergrowth in forest clearings and egdes of forest.
Breeds at 2400-3950 m in the Himalayas, up to 2900m in northeastern Indian hills and between 1200 m and 4900 m in China. At lower elevations in non-breeding season.

Behaviour

A shy and secretive species, often skulking for long periods in thick vegetation.
Has a distinctive habit of continually flicking wings and giving grating call when alarmed. Tail often slightly raised.

Diet

Not well known, feeds probably on invertebrates and larvae.
Forages low in dense vegetation.

Breeding

Poorly known. Breeding season from May to August. The nest is a ball made of dry grass, bamboo leaves and feathers. It's placed on the ground or low down in a clump of tall grass. Lays 3 to 4 eggs.

Movements

An altitudinal migrant, moves to lower elevations after breeding.

References

Clements, J. F., T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements checklist of Birds of the World: v2022. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/
Gill, F, D Donsker, and P Rasmussen (Eds). 2023. IOC World Bird List (v 13.2). Doi 10.14344/IOC.ML.13.2. http://www.worldbirdnames.org/
Del Hoyo, J, A Elliot, and D Christie, eds. 2006. Handbook of the Birds of the World. Volume 11: Old World Flycatchers to Old World Warblers. Barcelona: Lynx Edicions. ISBN 978-8496553064

List of references

Recommended Citation

BirdForum Opus contributors. (2025) Aberrant Bush Warbler. In: BirdForum, the forum for wild birds and birding. Retrieved 2 May 2025 from https://www.birdforum.net/opus/Aberrant_Bush_Warbler

External Links

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