The pygmy geese are a group of very small "perching ducks" in the genus Nettapus which breed in the Old World tropics. They are the smallest of all wildfowl. As the "perching ducks" are a paraphyletic group, they need to be placed elsewhere. The initially assumed relationship with the dabbling duck subfamily Anatinae has been questioned, and it appears they form a lineage in an ancient Gondwanan radiation of waterfowl, within which they are of unclear affinities. An undescribed fossil species from the late Hemphillian (5.0-4.1 mya) of Jalisco, central Mexico, has also been identified from the distal end of a tarsometatarsus. It is only record of the genus in the New World.
copyright: Martin Kennewell
Females have a white face with some grey spots, and obvious black areas beneath the eyes. The face of the male is more obviously white, and has green areas. The bodies of both have a tinge of red on the under carriage, with green markings on the rest of the body.
The species inhabits permanent or temporary swamps, marshes, inland deltas (e.g. the Okavango), shallow lakes, pools, farm impoundments, flood-plains, slow-flowing rivers and occasionally coastal lagoons. It shows a preference for deep clear waters with abundant emergent and aquatic vegetation, especially water-lilies (Nymphaea spp.).
Its diet consists predominantly of the seeds of water-lilies (Nymphaea spp.), although the seeds and vegetative parts of other aquatic plants (e.g. pondweeds Potamogeton spp.), aquatic insects and small fish may also be taken.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The species has declined is Madagascar as a result of hunting. It is also threatened by habitat degradation such as the destruction of aquatic plant communities through the introduction of exotic fish (e.g. cichlids Tilapia spp.), siltation, pollution (e.g. herbicides), drainage and tourist water-sports (which destroy lily beds).
The African Pygmy Goose has a lifespan of 10-15 years, reaching sexual maturity at two years. The species nests in natural hollows or the disused holes of barbets Megalima spp. and woodpeckers in trees, preferably those standing in or close to water. It may also nest in other cavities such as holes in cliffs or termites mounds, in the disused nests of Hamerkop Scopus umbretta, or in ground sites such as papyrus stands or grass clumps. Elevated nests are usually up to 10 m (occasionally 20 m) above the ground. The species will also nest in artificially erected nest boxes. The female goose will then lay an average of nine (8-12) eggs in a single clutch, which she will then incubate for three to four weeks. Fledging normally takes a further seven weeks.
This species is somewhat nomadic3 or partially migratory, making local dry-season movements dictated by habitat and water availability or dispersing to favoured moulting areas. The timing of the breeding season varies geographically but may be triggered by the rains2. The species usually nests in solitary pairs but is commonly found in small family groups outside of the breeding season, large concentrations of 10 to 200 individuals also forming during the dry season or at moulting sites.
Range: Africa : widespread. Senegal to Ethiopia southwards, except SW Africa; Madagasca