Madagascar grebe  (Tachybaptus pelzelnii)

This bird, like all other grebes, is a specialized waterbird, that is virtually unable to move on land, but is an excellent swimmer and diver. It is a small grebe, with soft, dense plumage that is white underneath and dark brown-grey on its upperparts (4) (5). When breeding, it has a distinctive facial pattern; the forehead and crown, down to the height of the eyes, are rusty black, which continues in a narrow line down the back of the neck. The throat and chin form a pale grey bib, which is separated by a white stripe from the red chestnut feathers behind the cheeks (2) (3). Non-breeding adults and juveniles are both duller and paler and lack the chestnut cheeks (2). Their small head and thin neck are perfectly streamlined for diving when searching for food, and its lobed, flexible toes are used to propel and steer them underwater, making grebes extremely agile swimmers (4). It has a grey to yellow bill and yellowish green feet (3).

As its name suggests, this bird is found throughout the island of Madagascar, except in the desert-like south (2).

Occurs on permanent or temporary water bodies, particularly shallow lakes and pools with abundant vegetation, especially waterlilies. It prefers still freshwater, but has been seen in brackish, and running water (2).

The Madagascar grebe feeds primarily on aquatic insects and crustaceans, and occasionally they will also take small fish (3). They obtain food by diving, or by seizing prey from the water's surface. They also consume feathers which form a ball in the centre of the stomach and a plug in the pyloric region. The main function of this may be to rid the grebe of gastric parasites when the ball is regurgitated (6). Madagascar grebes are territorial breeders that lay eggs from February to April, and August to October (2) (3). Their nests are floating platforms of aquatic plants, usually anchored well offshore in water lily areas, onto which clutches of three to four eggs are laid (6). If the pools or lakes that they inhabit dry up or reduce in size, these grebes will disperse to new water bodies (2).

The Madagascar grebe's total dependence on wetlands makes it very vulnerable to changes in these habitats. Indeed, the greatest threat to the Madagascar grebe comes from a reduction in its available habitat, as humans claim it for rice fields and fish farms (2). Introduced exotic, herbivorous fish (Tilapia melanopleura and T. zillii) have reduced the amount of aquatic vegetation, which makes the habitat more favourable for the competing Little Grebe, Tachybaptus ruficollis (2). The introduced predatory black bass (Micropterus salmoides), is also impacting the Madagascar grebe by preying on chicks and competing with the grebe for food (2). This species is also believed to be affected by water pollution and siltation; for example, it is considered rare in the area surrounding the capital of Madagascar, Antananarivo, due to the increased levels of water pollution (2). Entanglement in monofilament gill-nets, (large rectangular fishing nets that hang in the water like giant curtains), is also implicated in the decreasing numbers of this species (5).

The Madagascar grebe has been recorded from six protected areas (5), and probably occurs in more, but the number of grebes within each area is fairly small. In 1997 the IUCN Grebe Specialist Group created a Global Conservation Strategy to ensure the successful recovery of grebe populations and the management of wetlands. This is particularly important as grebes, due to their sensitivity to changes in wetland ecosystems, could be used as indicators of the health of such habitats. Particular conservation actions recommended for this species include carrying out a comprehensive survey and monitoring the population, to determine if numbers are declining and at what rate, and then researching factors for this decline (7).

For further information on the status and conservation of grebes see Grebes Status Survey and Conservation Action Plan, IUCN:
http://www.iucn.org/themes/ssc/actionplans/grebes/contents.pdf

Authenticated (19/06/07) by Professor Jon Fjeldså, Zoological Museum, University of Copenhagen.  
http://zoologi.snm.ku.dk/english/staff/