The 'Yellow-billed Duck', ''Anas undulata'', is a 51-58 cm long
dabbling duck which is an abundant resident breeder in southern and eastern
Africa.
This
duck is not
migratory, but will wander in the dry season to find suitable waters. It is highly gregarious outside the breeding season and forms large flocks.
These are
Mallard-sized mainly grey ducks with a darker head and bright yellow bill. The wings are whitish below, and from above show a white-bordered green speculum.
Sexes are similar, and juveniles are slightly duller than adults. The north-eastern race is darker and has a brighter bill and blue
speculum.
It is a bird of freshwater habitats in fairly open country and feeds by dabbling for plant food mainly in the evening or at night. It nests on the ground in dense vegetation near water. The clutch numbers between six and twelve eggs.
The male has a
Teal-like whistle, whereas the female has a Mallard-like quack.
The Yellow-billed Duck is one of the species to which the ''Agreement on the Conservation of African-Eurasian Migratory Waterbirds'' (
AEWA) applies. The southern
nominate subspecies is declining due to competition and
hybridization with feral
Mallards (Rhymer 2006).
References
★ Database entry includes justification for why this species is of least concern
★ 'Rhymer', Judith M. (2006): Extinction by hybridization and introgression in anatine ducks. ''Acta Zoologica Sinica'' '52'(Supplement): 583–585.
PDF fulltext
★ Ian Sinclair, Phil Hockey and Warwick Tarboton, ''SASOL Birds of Southern Africa'' (Struik 2002) ISBN 1-86872-721-1
★ Madge and Burn, ''Wildfowl'' ISBN 0-7470-2201-1