Gadwall
The gadwall (Mareca strepera) is a common and widespread dabbling duck[2] in the family Anatidae.
For other uses, see Gadwall (disambiguation).
The gadwall was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae.[3] DNA studies have shown that it is a sister species with the falcated duck; the two are closely related to the three species of wigeons, and all of them have been assigned to the genus Mareca.[4][5] There are two subspecies:[6]
The specific name strepera is Late Latin for "noisy".[8] The etymology of the word gadwall is not known, but the name has been in use since 1666.[9]
Description[edit]
The gadwall is 47–58 cm (19–23 in) long with a 78–85 cm (31–33 in) wingspan.[10] The male is slightly larger than the female, weighing on average 990 g (35 oz) against her 850 g (30 oz).[11] The breeding male is patterned grey, with a black rear end, light chestnut wings, and a brilliant white speculum, obvious in flight or at rest.[12] In non-breeding (eclipse) plumage, the drake looks more like the female, but retains the male wing pattern, and is usually greyer above and has less orange on the bill.[11]
The female is light brown, with plumage much like a female mallard. It can be distinguished from that species by the dark orange-edged bill, smaller size, the white speculum, and white belly.[12] Both sexes go through two moults annually, following a juvenile moult.[10]
The gadwall is a quieter duck, except during its courtship display. Females give a call similar to the quack of a female mallard but higher-pitched, transcribed as gag-ag-ag-ag. Males give a grunt, transcribed as mep, and a whistle.[11]
Distribution[edit]
The gadwall breeds in the northern areas of Europe and across the Palearctic, and central North America. In North America, its breeding range lies along the Saint Lawrence River, through the Great Lakes, Alberta, Saskatchewan, the Dakotas, south to Kansas, west to California, and along coastal Pacific Canada and southern coastal Alaska.[10][12] The range of this bird appears to be expanding into eastern North America. This dabbling duck is strongly migratory, and winters farther south than its breeding range, from coastal Alaska, south into Central America, and east into Idaho, Kansas, Ohio, Virginia, and then south all the way into Central America.[10][12]
In Great Britain, the gadwall is a scarce-breeding bird and winter visitor, though its population has increased in recent years. It is likely that its expansion was partly through introduction, mainly to England, and partly through colonization by continental birds staying to breed in Scotland. In Ireland a small breeding population has recently become established, centred on County Wexford in the south and Lough Neagh in the north.[13] The Gadwall is also seen in some parts of South Asia, particularly the southern part of India.[14]
Conservation[edit]
Currently, the gadwall is listed as least concern in the IUCN Red List of Threatened Species.[1] The gadwall is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. Populations have increased approximately 2.5% over the course of 49 years (from 1966 to 2010), and continue to grow. Gadwalls are one of the most hunted duck species (3rd to the mallard and green-winged teal), with 1.7 million shot each year.[19]
Because of the efforts of the United States and Canadian groups Ducks Unlimited, Delta Waterfowl Foundation and other private conservation groups, the species continues to be sustainably hunted there.[2]
Nest lined with feathers
Three males and two females resting
