Orange-headed thrush

Appearance

The orange-headed thrush is 205–235 milliimetres long and weighs 47–60 grammes. The adult male of the nominate subspecies of this small thrush has an entirely orange head and underparts, uniformly grey upperparts and wings, and white median and undertail coverts. It has a slate-coloured bill and the legs and feet have brown fronts and pink or yellowish rears.

The female resembles the male but has browner or more olive upperparts and wram brown wings, but some old females are almost identical to the male. The juvenile is dull brown with buff streaks on its back, and a rufous tone to the head and face; it has grey wings. The bill is brownish horn, and the legs and feet are brown.

This species' orange and grey plumage is very distinctive, and it is unlikely to be confused with any other species. Differences between the subspecies, as described above, can be quite striking, as with the strong head pattern on "Z. c. cyanotus", but may be less obvious variations in plumage tone, or whether there is white on the folded wing. As with other "Zoothera" thrushes, all forms of this species shows a distinctive underwing pattern, with a strong white band.

Distribution

The orange-headed thrush breeds in much of the Indian Subcontinent, including Bangladesh, India and Sri Lanka, and through Southeast Asia to Java. Its habitat is moist broadleaved evergreen woodlands, with a medium-density undergrowth of bushes and ferns, but it also utilises bamboo forests and secondary growth. "Z. c. cyanotus" also occurs in large gardens and orchards.

Status

The orange-headed thrush has an extensive range, estimated at 1–10 million square kilometres, The population size has not been quantified, but it is believed to be large as the species is described as “frequent” in at least parts of its range. The species is not believed to approach the thresholds for the global population decline criterion of the IUCN Red List, and is therefore evaluated as Least Concern.

It is very popular as cage-bird on Java, and numbers have severely declined in recent years owing to trapping for aviculture. Against the trend in Southeast Asia where loss or fragmentation of woodland poses a threat to forest birds, the orange-headed thrush has colonized Hong Kong, where it was first recorded in 1956, thanks to forest maturation.

Behavior

The orange-headed thrush is a shy, secretive bird usually occurring alone or in pairs, but is comparatively more easily seen than many other "Zoothera" thrushes, and several birds may congregate outside the breeding season at a good food source. It has a swift, silent flight, but when disturbed will often sit motionless until the threat has passed.

Habitat

This species is often found in damp areas, near streams or in shady ravines. It occurs between 250–1830 metres in the Himalayas and up to about 1500 metres in Malaysia, Thailand and Java. "Z. c. aurata" is resident between 1000–1630 metres on Mt Kinabalu and Mt Trus Madi, northern Borneo. Some of the subspecies are completely or partially migratory; their wintering habitat is similar to the breeding forests, but more likely to be at lower altitudes.

Reproduction

The nest, built by both sexes, is a wide but shallow cup of twigs, bracken and rootlets lined with softer plant material like leaves, moss and conifer needles. It is constructed at a height of up to 4.5 metres in a small tree or bush, with mango trees and coffee bushes being preferred. Three or four, occasionally five, eggs are laid; they are cream or tinted with pale blue, grey or green, and have pale lilac blotches and reddish brown spots. They are incubated for 13–14 days to hatching, with another 12 days until the young birds leave the nest.

This species is a host of the pied cuckoo, "Clamator jacobinus", a brood parasite which lay a single egg in the nest. Unlike the common cuckoo, neither the hen nor the hatched chick evict the host's eggs, but the host's young often die because they cannot compete successfully with the cuckoo for food. The chestnut-winged cuckoo, "Clamator coromandus", and, very rarely, the common cuckoo, "Cuculus canorus" have also been claimed as parasites on this species.

Food

The orange-headed thrush feeds on the ground in dense undergrowth or other thick cover. It is most active at dawn and dusk, probing the leaf litter for insect and their larvae, spiders, other invertebrates and fruit. In Malaysia, wintering birds regularly feed on figs.