Asian Openbill (Anastomus oscitans)

Kingfisher Wetlands, Sustainability Gallery, Bayfront MRT

The Asian Openbill (Anastomus oscitans) is a fascinating stork best known for the unusual gap in its bill. The distinctive shape is a clever adaptation  - together with the fine brush-like edges on the mandibles - that allows them to handle and extract soft bodies from hard shells with precision, making it a specialist feeder in wetland environments. They also supplement their diet with frogs, large insects, and occasionally small fish.

Standing tall (about 68-81cm) with pale grey plumage, black wing feathers, and long legs, the Asian Openbill is an eye-catching sight wherever it appears. Native to the Indian Subcontinent and mainland Southeast Asia, they inhabit and forage in shallow wetlands, marshes, rice fields, and flooded grasslands. While many populations are resident, Asian Openbills are known to move over long distances when water levels, rainfall, or food availability change. These movements can sometimes bring them far beyond their usual range.

The Asian Openbill is considered a rare visitor to Singapore. First recorded locally in 2013, it gained widespread attention between 2019 and 2021 when unusually large numbers appeared across the island. Often seen around wetlands, reservoirs, and parks, they have been observed feeding on snails in these freshwater habitats. This year, large flocks of them have been sighted at multiple waterbodies across the Gardens, including Kingfisher Wetlands, Sustainability Gallery and Bayfront MRT. 

Scientists hypothesised that their increased sightings in Singapore could be due to the increased population of the species from conservation efforts in Thailand, Cambodia and Vietnam, leading to their expansion in range. Given their adaptability to urban freshwater habitats and the availability of freshwater snails in Singapore, scientists suggest that there might even be potential for them to become residents eventually. These sightings highlighted the significance of our urban wetlands in our City in Nature as an important stopover and refuge for migratory birds.