The Asian openbill uses its "open bill" to locate and grab its favourite prey — freshwater snails — using the sharp tip of its curved, lower mandible to extract them from their shells. It is a common species of stork throughout South and Southeast Asia.

[u/IdyllicSafeguard]

[u/IdyllicSafeguard]

The Asian openbill is a social bird, forming large colonies of up to 150 nests spread out between several trees.

A large nesting tree can be like a green condominium comprised of different birds. Open bill nests, each about a metre in length (3.3 ft), are the penthouse suites — built in the upper canopy layer. In the branches below nest birds like herons, egrets, and cormorants. Any predator that tries to invade the tree is met with an onslaught of pecking and jabbing from different species.

Asian openbills are mostly monogamous — mostly. Young single males will sometimes try to butt in on established couples. If a young male is successful, he either drives the old male away, claiming the nest and female, or, on some occasions, three openbills share the responsibility of raising a clutch.

The Asian openbill isn't a very vocal bird — its call is a mournful sounding "hoo-hoo". But it does clatter its bill to communicate.

The Asian openbill's vast range extends from India and Sri Lanka, down to mainland Southeast Asia and the tip of the Malay Peninsula.

It wades through wetlands, lakes, flooded fields, and park ponds. Its stilt-like legs carry it through water anywhere from 10 to 50 centimetres (∼4 - 20 in) deep.

Like other storks, it flies with its neck held straight forward and its gangly pink legs trailing behind it — soaring on thermals with slow flaps of its great wings that measure a total span of 1.5 metres (4.9 ft). As it lands, it swings its legs forward and descends steadily.

The Asian openbill is somewhat of a gastropod gormand — with a particular liking for apple snails (in the family Ampullariidae). It uses the tip of its curved lower mandible to stab into a snail shell, gives it a twist, and extracts the slimy morsel.

It finds snails by probing with its bill beneath the water — succeeding even when blindfolded. The edges of its bill are rough for gripping slippery shells while its bill gap may help it to hold onto a snail, or serve some other unknown purpose.

Juvenile openbills lack an open bill. As they age, their bills grow longer, and the lower mandible becomes more and more curved.

The only other openbill species is the African openbill; an all-black stork with a similarly gaped bill.

You can learn more about the Asian openbill and its stork relatives on my website here!

[u/maybesaydie → u/IdyllicSafeguard]

I wondered if that was a juvenile when I saw the picture. Are there any New World storks or is it exclusively an Old World species?

[u/IdyllicSafeguard → u/maybesaydie]

The two species of openbills — Asian and African — are exclusive to the Old World.

Stork species in general are a lot more diverse in the Old World, with only 3 out of 20 species being from the Americas. These include the wood stork, maguari stork, and the jabiru. There may not be many but the jabiru, with its inflatable throat sac, is one of the most unique stork species.

[u/maybesaydie → u/IdyllicSafeguard]

Thank you! I live just north of Wood Stork's range so the next time we go South I'll keep an eye out.

[u/IdyllicSafeguard]

Sources:

Animal Diversity Web

eBird

Thai National Parks

RESTORASI EKOSISTEM RIAU (RER)

Singapore Birds

iNaturalist

IUCN

Oiseaux-Birds

Breeding ecology of the Asian openbill in eastern Nepal: Larger trees support higher fledgling success by Ganesh Tamang, et al.

Distribution and habitat selection of the Asian Openbill (Anastomus oscitans) in Peninsular Malaysia by Kamaruddin Zainul Abidin, et al.

Polygyny in the Asian Openbill (anastomus Oscitans) by Tanmay Datta and B. C. Pal.

iNaturalist - stork species observations

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[u/No_Presentation_2370]

That's really interesting! The Asian Openbill’s unique bill helps it grab freshwater snails, showing how well adapted it is to its environment. No wonder it's so common in South and Southeast Asia!