Yellow-billed Duck (Anas undulata)

Yellow-billed Duck

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas undulata | [authority] Dubois, 1839 | [UK] Yellow-billed Duck | [FR] Canard a bec jaune | [DE] Gelbschnabel-Ente | [ES] anade Picolimon | [NL] Geelsnaveleend | [copyright picture] Steelback


Genus Species subspecies Region Range
Anas undulata AF ec, sc, s


Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank.[1] Indeed, as the moa-nalos are very close to this clade and may have evolved later than some of these lineages, it is rather the absence of a thorough review than lack of necessity that this genus is rather over-lumped. The phylogeny of this genus is one of the most confounded ones of all living birds. Research is hampered by the fact the radiation of the two major groups of Anas ? the teals and mallard groups ? took place in a very short time and fairly recently, roughly in the mid-late Pleistocene. Furthermore, hybridization may have long played a major role in Anas evolution, with within-subgenus hybrids regularly and between-subgenus hybrids not infrequently being fully fertile.[1] The relationships between species are much obscured by this fact, and mtDNA sequence data is of dubious value in resolving their relationships; on the other hand, nuclear DNA sequences evolve too slowly to resolve the phylogeny of the subgenus Anas for example. Some major clades can be discerned. For example, that the traditional subgenus Anas, the mallard group, forms a monophyletic (in the loose sense, i.e. non-holophyletic) group has never been seriously questioned by modern science and is as good as confirmed (but see below). On the other hand, the phylogeny of the teals is very confusing. For these reasons, the dabbling duck lineages more distantly related to mallard group (which includes the type species of Anas) than the wigeons should arguably be separated in their own genera. These would include the Baikal Teal, the Garganey, the spotted black-capped Punanetta group, and the shovelers and other blue-winged species. Whether the wigeons, which are very distinct in morphology and behavior, but much less so in mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequences, should also be considered a distinct genus Mareca (including the Gadwall and Falcated Duck) is essentially the one remaining point of dispute as regards the question which taxa should remain in this genus and which ones should not.

Physical charateristics

Head and neck blackish grey with pale streaking, upperparts and underparts dark brown with pale feather edges. Wing has secondaries iridescent green, bordered in black and with white feather tips. White tips also to dark grey greater coverts (speculum green bordered with black and white). Anas undulata ruppelli darker (narrower pale feather edging), secondaries iridescent blue rather than green. The bill is bright yellow, black stripe down culmen (not reaching end of bill), black nail and cutting edges. Female has paler yellow bill, Anas undulata ruppelli more yellow-orange.

Listen to the sound of Yellow-billed Duck

[audio: Duck.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 51 cm size max.: 58 cm
incubation min.: 26 days incubation max.: 29 days
fledging min.: 66 days fledging max.: 70 days
broods: 1   eggs min.: 4  
      eggs max.: 12  


Africa : Eastcentral, Southcentral, South. Anas undulata ruppelli southern Sudan, Ethiopia, Uganda, northern Kenya. Anas undulata undulata southern Kenya, westward to Angola, southward through southern Africa to Cape Province.


Freshwaters, lakes, swamps, marshes, flooded fields, reservoirs, slow-flowing rivers, also brackish coastal lagoons, and estuaries. To 3890m in Ethiopia, otherwise usually lowlands.


Variable, extended breeding season but peak usually in rainy season. Opportunistic breeder. Nest is built, by the female only, in thick vegetation near water. Clutch size 4-12 eggs which are incubated by the female for about 26-29 days. YOung are able to fly in about 68 days. Newly-hatched are cared for by female only. Broods sometimes merge, so ducklings seen with two adult ducks. Juveniles remain with female for about six weeks after fledging. Seasonal monogamy, male leaves mate once incubating.

Feeding habits

May travel some distance from loafing areas to feed. Feeds mainly at dusk and after dark/ Diet consists of seeds, green parts and roots of aquatic and terrestrial plants, also invertebrates ? insects and insect larvae, molluscs, crustaceans

Video Yellow-billed Duck


copyright: Josep del Hoyo


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). The population trend appears to be stable, and hence the species does not 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.
Yellow-billed Duck status Least Concern


Mainly sedentary with some local movements or some longer distances reported.

Distribution map

Yellow-billed Duck distribution range map

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