Sacred Ibis

Characteristics

The Sacred Ibis is a large wading bird, with a long, thin down-curved black bill. The body is white all over, except for the tail and wingtips which have long black plumes. The head and neck are also black, but lack feathers. Legs and feet are black as well. When the wings are open, patches of pink or red skin can be seen along the underside of the wing and sides of the breast. Juveniles look similar, but have mottled white and black feathers on the head and neck, which they lose once they are about 2 years old.

Species Specifics

Similar species to the Sacred Ibis are the Australian White Ibis (native to Australia) and the Black-headed Ibis (native to Asia). The Black-headed Ibis, in addition to having a completely different range, also is lacking the black tail and wingtips of the Sacred Ibis. The Australian White Ibis is considered by some to be a sister species, but its range is limited to Australia.There are three subspecies of Sacred Ibis. The nominate species, T. a. aethiopicus, is the largest of the subspecies, and found across Africa and has colonized small areas of Europe. It has brown irises. T. a. abbotti is found on the Aldabra Atoll only, and is smaller with a thinner bill, no neck sack, fewer black flight feathers, a black stripe on the underside of the wing, and a blue iris. T. a. bernieri is found on the island of Madagascar and has a similar size to T. a. abbotti, but it lacks the black stripe on the underside of the wing and its irises are pale blue or white.

Physical Characteristics

Long legs and a wide foot with toes spread apart help the Sacred Ibis while it forages for food. The wide foot helps spread out the weight of the bird so it does not sink into the mud.

Ecology

Habitat

Sacred Ibises are found in wetlands, river systems in open woodlands, coastal lagoons, marshes, salt pans, dams, mangroves, as well as areas utilized by humans such as refuse dumps, farms, and cultivated fields.

Distribution

The Sacred Ibis may travel between 10 and 30 kilometers away from the colony roosting site to forage for food. Additionally, the nominate subspecies, T. a. aethiopicus, is an intra-African migrant, moving several hundred kilometers to breed. The species does not cross the equator during this movement; if the bird is north of the equator, they migrate to the north. If the bird is south of the equator, they migrate south.

Diet

The Sacred Ibis is an opportunistic carnivore. It eats mainly snails, aquatic invertebrates, and frogs. They will also eat eggs and young birds, small reptiles and mammals, and will scavenge as well.

Ecological Web

The Sacred Ibis is a large bird, and this somewhat discourages predation. However, the eggs and nestlings of the Sacred Ibis can be easily predated. It is a predator of many small vertebrates and invertebrates and helps keep these populations in check. It also helps aerate the soil in areas it forages by probing the ground with its bill for food. In areas of Europe where it is considered an invasive pest, there is concern that it is consuming threatened native wildlife and competing for territory with native wildlife.

Activity and Behavior

Activity Pattern

The Sacred Ibis forages during the day, sometimes traveling between 10 and 30 kilometers away from the roost. They forage with other birds, and return to the roost at night.

Behavior

As a very adaptive bird, the Sacred Ibis will sometimes forage around humans. They will gather at refuse dumps or farmlands.

Social Behavior

The Sacred Ibis is a gregarious bird, and forages in small groups of between 2 and 20 individuals, though flocks as large as 500 have occasionally been observed. During the breeding season, they form mixed species colonies of 50 to 20,000 breeding pairs.

Reproductive Behavior

The breeding season starts during the rainy season, which is from March to August in Africa and April and May in south-eastern Iraq. Sometimes, the Sacred Ibis migrates to a breeding colony, others are sedentary. Males usually arrive first and select a spot to form pairing territories, which they will defend by standing with wings open and feathers spread out. They may engage in striking other males with their bills in territory disputes while making a squealing sound. Females arrive a couple of days later. The female approaches the male and if she is not chased away, the pair bows to each other with necks fully extended. Both male and female assume an upright standing position afterward, with necks and bills intertwined. More bowing and preening may occur, and then the pair moves off to an area selected by the female and copulation occurs there. The pair will continue to defend their territory and nest. When another bird approaches, the Sacred Ibis will stand with wings open, head lowered and bill open to the intruder. However, to greet their mate the Sacred Ibises standing close to one another, wings open, head raised and vocalizing. Nests are large, loose platforms made of sticks and lined with leaves and grass. The males retrieve nest materials and bring them to the female who constructs the nest. When materials are in short supply, males may steal materials from other nests. Nests may be 27-37 cm in diameter and 10-15 cm high, and no more than 6 meters off the ground. They are often grouped together with other Sacred Ibises, a sub colony within a mixed species colony, and so close together that sometimes a common platform is constructed. Once a nest is complete, 2-3 eggs will be laid. Incubation is carried out by both male and female.

Offspring

Between 2-3 pale eggs with a blue or green tinge are laid, though nests with as many as 5 eggs have been recorded. The male and female take turns incubating and guarding the nest for about 28 days, in day-long shifts. Once the chicks have hatched, the parents identify their offspring and then bring them food. Both male and female with feed and care for their offspring, with one of the pair remaining at the nest to guard the nestlings while the other forages for food. Chicks fledge after 35-40 days, and parents continue to feed their offspring. The fledglings become independent around 44-48 days.

Conservation

Status

Classified as Least Concern on the IUCN in 2016, and not listed on the CITES appendices.

Historical

The Sacred Ibis's range once extended into Egypt, but it is now regionally extinct there. It was listed on CITES Appendix III by Ghana in 1976, but was removed in 2007.

Current Threats

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