Asian Openbill - Anastomus oscitans

Asian Openbill

Anastomus oscitans

Order : Ciconiiformes

Family : Ciconiidae ;

Biometrics :

Size : 76 à 81 cm
Wingspan : 147 à 149 cm
Weight :

IUCN conservation status :

Extinct

Threatened

Least
concern

Extinc
in the Wild

Near
threatened

Not
evaluated

EX EW CR EN VU NT LC NE

Geographic range :

Synonyms : Аист-разиня инди (ru), Picotenaza Asiático (es), Anastomo asiatico (it), Silberklaffschnabel (al), Indische Gaper (nl), Asian Openbill (en)

Physical description :
Asian Openbill is a small stork with conspicuous gap in its bill. Adult has white plumage in breeding season, and pale grey for rest of the year. Scapulars, flight feathers and tail are black.
Head is white or grey. The open bill is formed by a hollow in the lower mandible. Both mandibles meet at tip. Large, strong bill is pale pinkish-grey. Eyes are dark brown. Lores are greyish to pinkish. Long legs and feet are pinkish to red.
Both sexes are similar.
Juvenile have brown tinge, instead white or pale grey. Bill is dark grey with lower mandible almost straight. Gap forms later.

Voice : Asian Openbills are very noisy while flying in flocks. We can hear a continual hubbub, as the gabbling of hundreds of ducks. Call is a mournful 'hoo-hoo'.

Habitat : Asian Openbill feeds in rice-fields and marshes in freshwater. It breeds near inland wetlands. It lives in shallow marshes and flooded areas.
GEOGRAPHIC RANGE: Asian Openbill is resident in tropical southern Asia, from India and Sri Lanka, east to south-eastern Asia.

Behaviour : Asian Openbill feeds mainly on molluscs, and particularly freshwater snails, Apple Snails, (genus 'Pila' - Ampullariidae), living in rice-fields and swamps. Prey is located by touch and sight. The gap in the bill allows good grasp of the snail's shell. Asian Openbill walks slowly in shallow water, searching for prey. It extracts snail from the shell, with pointed lower mandible.
Asian Openbill populations are resident in their range. Some groups may move after breeding season, but most of them are sedentary. Breeding season depends on the location. Northern populations breed from July to September, and southern birds breed from November to March. They are very social birds.
Asian Openbill nests in colonies, with numerous nests in the same tree, up to 40 and more. Long courtship displays occur at the beginning of breeding season.
In threat displays, Asian Openbill has open wings and neck outstretched. Usually, rivals threaten each other, but rarely fight.

Flight : Asian Openbill uses warm airstreams for rising in the air, and flies high in the sky. Then, it glides to destination.
Landing is spectacular. Asian Openbill drops from the air as a parachute, with dangling legs, and lands.

Reproduction-nesting : Asian Openbill nests in colonies with other species, such as ardeidae. Nest is located in trees or bamboos. It is made with sticks, and interior is lined with green leaves.
Female usually lays 2 to 4 white eggs. Incubation lasts about 27 to 30 days, and young fledge at 35 to 36 days after hatching.
Young birds are greyish, with dark bill. They stand and wait for adults. Parents approach the nest cautiously, and regurgitate the food.
Adults shade their young in the nest, to protect them from sun. One of the parents stands in the nest with semi-open wings above the chicks.
Asian Openbill is usually monogamous, but polygyny exists. In this case, all members of polygynous nest raise the young, and brood success is more important than in monogamous nests.

Food habits : Asian Openbill feeds mainly on Apple Snails, but it also consumes frogs, crabs and large insects, and other small aquatic animals.

Protection / threats : Asian Openbill is the most common Asian stork, and populations are not threatened.
Most important colonies are protected, as those of Wat Pai Lom and San Lon, in Thailand.

Other links :
Iucn
Birdlife

Specification sheet created by Nicole Bouglouan

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Updated on 2008/04/29 05:36:33 - © 1996-2008 Oiseaux.net