Madagascar sacred ibis (Threskiornis bernieri)
|Size||Length: 65 – 89 cm (2)|
Classified as Endangered (EN) on the IUCN Red List (1).
Previously considered a subspecies of the African sacred ibis (Threskiornis aethiopicus) (1), the common name of these distinctive birds derives from the fact that they were revered by the ancient Egyptians (3). Like its African relative, this bird has starkly contrasting colouring, with the body being mainly white, except for a portion of the tail feathers, which are developed into large, dark ornamental plumes, and the bill, head, neck and legs, which are completely bald and black. The colouring of the body feathers varies between individuals, with some having black wing tips, while others are completely white. The Madagascar species can be differentiated from its African counterpart by its smaller size and pale blue eyes (2) (4). Juveniles possess downy white and greyish feathers on the head and neck, which are lost as the bird matures. A variety of vocalisations are produced by the Madagascar sacred ibis, including groans, squeaks and hisses (4).
The Madagascar sacred ibis is confined to the west coast of Madagascar and Aldabra, a coral atoll approximately 400 kilometres north-west of Madagascar. The two locations harbour different subspecies of the bird, with Threskiornis bernieri bernieri found on Madagascar and Threskiornis bernieri abbotti found on Aldabra (2).
The Madagascar sacred ibis is mainly found in lowland regions around coastal zones where the water is either salty or brackish (1), such as: coral lagoons (4); shallow, coastal lakes; mudflats; estuaries; and mangroves. They have also been sighted in inland rice fields and in freshwater lakes within forested areas, though these are not considered to be major habitats for this species (1).
The Madagascar sacred ibis can be found wading through areas of shallow water within its habitat, the long, slender legs raising the body well above the water level (3). When feeding, the Madagascar sacred ibis extends its sinuous neck down to the water and uses its elongated bill to probe above or within the sediment for small invertebrates such as worms, snails and crustaceans (2) (3). It may also take small vertebrates such as frogs and reptiles (1).
The Madagascar sacred ibis breeds in colonies, which are often found mixed amongst the breeding colonies of various heron species. The ibis constructs a small nest from twigs, in which it lays a clutch of two eggs. The nest is usually situated in a tree, although, on Aldabra, the Madagascar sacred ibis may also position its nest on the ground (2).
The main threats to the Madagascar sacred ibis come from the harvesting of its eggs, the trapping of adults and the taking of chicks for human consumption. Estimates of this species’ population on Madagascar in 2006, indicated that there were less than 2000 mature individuals, a number that is simply too small to support the current levels of exploitation. Unfortunately, the Madagascar sacred ibis displays no fear of humans while nesting or roosting, and is, therefore, an easily obtainable source of food for hunters. While legislation on hunting does exist in Madagascar, it has proved ineffective in reducing hunting pressure on this species, with surveys indicating that populations of the Madagascar sacred ibis are significantly declining (2).
Like other large water birds found in coastal wetlands, the Madagascar sacred ibis is also threatened by the degradation and loss of its habitat (1) (2). Pollution and sedimentation are two of the main contributors, with excess sediment being generated from increased soil erosion, as a result of slash-and-burn deforestation methods. Important habitat provided by mangroves is also being lost, as the trees are cut down for charcoal production (2).
The Aldabra population of the Madagascar sacred ibis, estimated in 2001 to be around 300 to 750 individuals, currently receives significant protection (2). The entire atoll is designated a Strict Nature Reserve and a Natural World Heritage Site, and only small scale ecotourism, deep-sea fishing and limited exploitation of some resources are permitted. However, the conservation of the island and enforcement of its protection are the responsibility of the Seychelles Island Foundation, which requires subscriptions and donations in order to fund its valuable work (5).
In Madagascar, the conservation of the Madagascar sacred ibis is much less stringent; currently, 70 percent of its population is found outside of protected areas. In those areas that are protected, enforcement of legislation is lacking. Hence, there is a clear requirement for the improvement of this enforcement and for the creation of additional areas of protection (2). Recently, there have been some positive developments towards this goal; in 2005 the Malagasy Association Voronosy was formed to specifically protect the Madagascar sacred ibis in the region of Bombetoka Bay. The programmes implemented by this organisation have helped to educate local people about the plight of this species and there are now plans to develop local protected areas. The organisation also intends to benefit the livelihoods of the local people by giving them the chance to offer eco-tourism boat trips, and develop the use of alternative sources of food, such as keeping egg-laying hens (6). As a measure of the organisation’s success, the programs that they have already implemented resulted in an increase in numbers of young birds in 2006. The conservation organisation, BirdLife, is also working towards protecting this species. As a result of its ongoing Madagascar Action Plan, in 2007, a temporary decree was made to protect the Mahavavy-Kinkony Wetlands, an area of almost 3,000 square kilometres that harbours a significant number of Madagascar sacred ibis. The organisation is currently working towards making this a permanent zone of protection (7). Conservation efforts such as these will help to assure the survival of this distinctive bird and the other threatened species with which it shares its habitat.
For further information on conservation in Madagascar:
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- Brackish: slightly salty water.
- Invertebrates: animals with no backbone.
- Ornamental plumes: Long, conspicuous feathers, distinct from the rest of a bird’s plumage
- Slash-and-burn: the cutting and burning of forests or woodlands to create space for agriculture or livestock.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- Vertebrates: animals with a backbone.
IUCN Red List (October, 2008)
BirdLife International (October, 2008)
- Burnie, D. (2001) Animal. Dorling Kindersley, London.
- Sinclair, I. and Langrand, O. (2004) Birds of the Indian Ocean Islands. Struik Publishers, Cape Town.
World Database on Protected Areas (October, 2008)
Conservation des Espèces et des Populations Animales (CEPA) (October, 2008)
BirdLife International (October, 2008)