Oriental Reed Warbler

The Oriental reed warbler, Acrocephalus orientalis, is a robust passerine bird that graces the eastern Asian landscape. This large warbler measures 18–20 cm in length with a wingspan stretching 23–26 cm. Its plumage is a study in subtlety, with brown upperparts that transition to a paler rump, and the tail feathers are tipped with a modest white. Below, the bird is dressed in whitish hues, with the flanks and undertail-coverts taking on a more earthy brown. A keen observer will note narrow greyish streaks adorning the throat and breast. The bird's face is marked by a dark eyestripe and a contrasting whitish supercilium. Its bill is a sturdy affair, brownish on top and pink below, with a strikingly bright orange gape. Grey feet complete the ensemble.

Identification Tips

When comparing with its relatives, the Oriental reed warbler is slightly smaller and more slender than the great reed warbler, with shorter wings to match. Its tail is more square-ended than that of the clamorous reed warbler, and it boasts a slightly longer primary projection. The bill is a touch shorter and thicker. One can distinguish it from its congeners by the pale tip of its tail.

Habitat

The Oriental reed warbler is a creature of reedbeds, though it is also at home in marshes, paddy fields, grasslands, and scrub. These varied habitats provide ample foraging opportunities for this insectivorous bird.

Distribution

This warbler's breeding grounds span southern Siberia, Mongolia, northern, central, and eastern China, Korea, and Japan. Come winter, it migrates to north-east India and across South-east Asia, reaching as far as the Philippines and Indonesia, with occasional sightings in New Guinea and Australia. It has also been recorded as a vagrant in Israel and Kuwait.

Behaviour

The Oriental reed warbler is known for its small breeding territories and the potential for high population densities. It is an active forager, seeking insects and other invertebrates to sustain itself.

Song & Calls

The warbler's song is a delightful medley of warbling phrases interspersed with guttural, croaking notes, often delivered from a prominent perch. Additionally, it communicates with a loud, harsh "chack" call.

Breeding

Nests are artfully constructed 1–1.5 metres above the ground amidst reed stems. Clutches typically contain two to six eggs, which are incubated for 12 to 14 days. The fledglings take their first flight after 10 to 15 days. Predators such as the Siberian weasel, cats, and snakes from the genus Elaphe pose a threat to the nests.

Similar Species

The Oriental reed warbler can be confused with the great reed warbler and the clamorous reed warbler, but careful observation of its tail, primary projection, and bill size can aid in correct identification.

Diet and Feeding

This warbler's diet consists primarily of insects and other small invertebrates, which it actively seeks out in its diverse habitats.

Conservation status

The IUCN Red List categorizes the Oriental reed warbler as Least Concern, indicating that, for now, this species does not face immediate threats to its survival.