Giant Ibis

Scientific Name: Thaumatibis gigantea

Classification: Order: Pelecaniformes; Family: Threskiornithidae

Giant Ibis

Brief Description

The world's largest ibis, recognized by its massive size, long down-curved bill, and bald head. It is a shy, terrestrial bird that forages in forest pools and marshes.

Additional Information

  • Region of Origin: Mainland Southeast Asia (Cambodia, Laos, Vietnam)
  • Typical Sighting Period: Year-round, though best observed during the dry season (November to May) when they congregate near water sources.
  • Plumage Details: Adults have dark greyish-brown plumage with a greenish-bronze sheen on upperparts. The head and upper neck are bare and greyish, showing dark bands on the nape. Juveniles are duller with short feathers on the head and a smaller bill.
  • Ecological Significance: As a large predator of invertebrates and small vertebrates in seasonal wetlands, it plays a key role in the nutrient cycling of dipterocarp forest ecosystems.
  • Conservation Status: Critically Endangered (IUCN Red List); population is extremely small and declining due to habitat loss and disturbance.
  • Observation Tips: They are extremely wary of humans. Best observed from hides near 'trapaengs' (seasonal forest pools) in the Northern Plains of Cambodia at dawn or dusk.

Size & Weight

Length: 102–106 cm (40–42 in); Weight: approximately 4.2 kg (9.3 lbs).

Diet

Feeds on aquatic invertebrates, crustaceans, small amphibians, reptiles, and seeds by probing the mud with its long bill.

Habitat

Lowland deciduous dipterocarp forests with scattered seasonal wetlands and marshes.

Migration

Non-migratory/Resident, though it may move locally in response to water availability.

Voice (Call & Song)

A loud, haunting, ringing 'a-leur a-leur' or 'a-ga-loh', typically heard at dawn or dusk.

Nesting & Breeding

Nests high in large trees (often Dipterocarpus trees) during the rainy season. Usually lays two eggs; breeding pairs are highly sensitive to human presence.

Key Field Marks

Massive size, bald grey head with black stripes on the nape, and a long, heavy, downward-curving bill.

Similar Species

White-shouldered Ibis (Pseudibis davisoni), which is significantly smaller and has a distinct white patch on the shoulder and a pale collar.

Interesting Facts

The Giant Ibis is the national bird of Cambodia. It was once thought to be extinct until it was rediscovered in the late 20th century.