Order: Pelecaniformes
Family: Threskiornithidae
Size: up to 65 - 76 cm in length
Weight: up to 1.5 kg
Key Features: It is a large, white waterbird with a prominent bare black head and neck, and a long, down-curved black bill. The body of this species is elongated but robust. The tail of the black-headed ibis bears grey ornamental feathers, in contrast to its close relative the African sacred ibis (Threskiornis aethiopicus), in which these feathers are black. Both the male and female black-headed ibis are similar in size and appearance. During the breeding season, bare patches under the wings turn a blood red colour, the head can develop a blue tinge and the legs often become glossy black. The breeding adult also develops a loose ruff of white feathers on the lower neck and sometimes a yellowish wash on the breast and back. Juvenile black-headed ibises have grey feathers on the head and a white neck, and it is three years before the full adult plumage is acquired.
Voice: It is usually a silent bird, but when males and females are courting they are known for their loud booming calls and low grunting.
Breeding: When courting, male black-headed ibises perform display flights and show off their ornamental plumes, and they will often spar with other males, thrusting their bill at opponents. The male will advertise to females by popping its bill and rubbing its head, and when pairing up both the male and female will ‘bow’ before mating. The displays of the black-headed ibis are notably much less aggressive than in the closely related African sacred ibis (T. aethiopicus). During mating, the male black-headed ibis straddles the female and grasps with its bill. Afterwards, the nest is built, with the male collecting sticks and the female arranging them. The nests of this species are around 30 centimetres wide. Between 2 and 4 eggs are laid, and are incubated for 23 to 25 days. However, it is rare that more than 2 young survive to fledge around 40 days later due to predation by crows and humans, as well as over-heating.
Diet: It is primarily carnivorous, with a diet that includes frogs, tadpoles, snails, insects and worms. More coastal populations will also eat fish and crustaceans, and the black-headed ibis has also been found to sometimes eat vegetable matter.
Habitat: It is predominantly a wetland bird, and lives mainly in lowland areas not more than 950 metres above sea level. It frequently inhabits swamps, lake and river margins, wet grasslands and paddy fields. More rarely it is also found in tidal mudflats, mangroves and brackish lagoons.
Habits: To obtain food, the black-headed ibis usually probes with its bill in mud and shallow water, and can submerge its entire head and neck while wading if needed. It will also feed on dry land from time to time, but moves around as tides change. Interestingly, the black-headed ibis will sometimes associate with grazing buffalos, taking insects that are thrown up as the buffalos move around.
Conservation Status: Near Threatened on the IUCN Red List of Threatened Species.
References:
del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
Kennedy, R.S., Gonzales, P.C., Dickinson, E.C., Miranda Jr, H.C. and Fisher, T.H. (2000) A Guide to the Birds of the Philippines. Oxford University Press, Oxford.
Hancock, J.A., Kushlan, J.A. and Kahl, M.P. (1992) Storks, Ibises and Spoonbills of the World. Princeton University Press, New Jersey.
Brazil, M. (2009) Birds of East Asia. A&C Black Publishers, London.
Photo Courtesy
K Hari Krishnan, Licensed under CC BY-SA 3.0 via Wikimedia Commons
Black-Headed Ibis (Threskiornis melanocephalus)
