The black-headed ibis is a social species, feeding and nesting in groups (2). It is primarily carnivorous, with a diet that includes frogs, tadpoles, snails, insects and worms. More coastal populations will also eat fish and crustaceans (2), and the black-headed ibis has also been found to sometimes eat vegetable matter (4).
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 (2). It will also feed on dry land from time to time, but moves around as tides change (4). Interestingly, the black-headed ibis will sometimes associate with grazing buffalos, taking insects that are thrown up as the buffalos move around (2).
This species nests in well protected areas, often in colonies which include other species of heron and stork (4). It builds its nest in trees near to water, or in partially submerged shrubs. The breeding season of the black-headed ibis is determined by the monsoons, and it will often begin pairing up after the rains are over (4).
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 (4). 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 (4). The nests of this species are around 30 centimetres wide (4). 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 (2).