American Wigeon (Anas americana)

American Wigeon

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas americana | [authority] Gmelin, 1789 | [UK] American Wigeon | [FR] Canard de Amerique | [DE] Nordamerikanische Pfeifente | [ES] Silbon Americano | [NL] Amerikaanse Smient

Subspecies

Genus Species subspecies Region Range
Anas americana NA widespread

Genus

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

A small duck with a short bill and round head, the American Wigeon has a reddish-brown body, and a speckled grayish head that is plain in females and boldly patterned in males. Its bill is blue-gray with a narrow black border at the base, and its feet are dark gray. Apparent in flight, the speculum, or wing-patch, is dark iridescent-green, looking black at times, with white on the forewing. The male has distinctive, black undertail coverts, a white forehead, and iridescent green band sweeping back from the eye. Females, juveniles, and eclipse-plumage males lack these markings. Males are usually in eclipse plumage in the post-breeding, pre-migration period from July to September. Extremely wary, the American Wigeon is often difficult to get a good look at, as most are quick to take flight when approached; however the loud distinctive whistle it gives is usually a clear indicator.

Listen to the sound of American Wigeon

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/American Wigeon.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by Macaulay


wingspan min.: 76 cm wingspan max.: 89 cm
size min.: 48 cm size max.: 56 cm
incubation min.: 23 days incubation max.: 25 days
fledging min.: 36 days fledging max.: 25 days
broods: 2   eggs min.: 6  
      eggs max.: 12  

Range

North America : widespread

Habitat

Breeding Wigeon tend to choose sluggish rivers, marshes and shallow ponds with exposed shorelines and submergent vegetation, adjacent to dry meadows. When raising broods, American Wigeon prefer more open water, unlike most other dabbling species. Migrating Wigeon rely on small and large lakes, quiet rivers, flooded fields and protected freshwater inlets where food is plentiful. Winter habitat includes freshwater lakes, rivers, marshes and sheltered estuaries and bays.

Reproduction

American Wigeoans are one of the earliest waterfowl to reach their wintering grounds, by this time male and female Wigeon have already formed pair bonds, with pair formation usually complete by February. Males have several courtship displays, such as swimming with heads thrust forward and wings pointed upwards, as well as facing the females with wings pointed upwards and dipping their bills into the water. An unseemly courting ritual is “the burp,” in which the male emits high-pitched vocalization while stiffening his upper head feathers and his body in an erect posture, either ahead, behind, or beside a female. Like most ducks, American Wigeon are considered to be monogamous. Therefore, males usually stay with their mates through spring migration, nest selection, nest building and egg laying, leaving her alone at the end of incubation to group with other males and non-breeding females to molt.

Because it is a secretive duck and often nests in relatively remote landscapes, less is known about the American Wigeon’s breeding habits. Nests are typically located on dry ground, up to 400m from the shoreline, where the nest can be carefully concealed in tall vegetation. Sometimes the female will nest in ground scrapes, lining the nest with leaf litter and covering the eggs with down when leaving to forage. The female will lay 9-12 eggs on average, and incubation occurs over approximately 25 days. Soon after her eggs have hatched, the female removes the precocial ducklings from the nest to the preferred brood habitat (mentioned above). Some species will allow other ducklings to join their broods; the female Wigeon, however, will aggressively prevent this, even with other Wigeon ducklings. To protect her brood from predators, the female will often use a distraction display, such as feigning wing injury, to distract the predator while her ducklings either dive or seek cover in surrounding vegetation, then fly off once the ducklings are concealed. Ducklings do not rely on their mother and feed themselves, relying on mostly insects for several weeks; eventually dabbling and consuming mostly aquatic vegetation. Females typically leave their young either before they fledge (approximately 6 weeks), or, if the female remains at the brood site to molt, after fledge.

Feeding habits

The American Wigeon’s preferred foods are leaves and roots of submergent vegetation. As a dabbling duck, they are poor divers, making it difficult for them to obtain this food, so they do the next best thing: steal from those that can. Wigeon are often seen with diving species such as canvasbacks, redheads, scaup and coots, and they have also been known to steal from geese and even muskrats. They wait until these species dive to collect submergent vegetation, and then steal what they lose or sometimes snatch it straight from their mouths. As a result, the Wigeon has been nicknamed “the poacher.” During the breeding and brood season, the American Wigeon’s diet also consists of aquatic invertebrates, such as insects and mollusks; during migration, it will graze on upland grasses, clovers and some agricultural crops.

Video American Wigeon

httpv://www.youtube.com/watch?v=hf7xmp9_Ouc

copyright: youtube


Conservation

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 extremely 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 American Wigeon population experienced a major, drought-induced decline in the early 1980s, cutting the population almost in half. By 1997, the population had steadily recovered to near-former levels and is considered stable. The breeding grounds are fairly stable for this far-north breeder, although migration stopover and wintering sites are threatened by the loss of wetlands that has occurred throughout the United States.
This dabbling duck is migratory and winters farther south than its breeding range, in Texas, Louisiana, and other areas of the Gulf Coast. It is a rare but regular vagrant to western Europe. It is highly gregarious outside of the breeding season and will form large flocks.
American Wigeon status Least Concern

Migration

Winters mostly along both Atlantic and Pacific coasts of North America and Iceland S to Panama; also on Bermudas and Hawaii. Occurs in very small numbers on eastern side of N Atlantic, where regular in Britain. Vagrants have also reached NE Siberia and Japan.

Distribution map

American Wigeon distribution range map

Literature

Title Activity budgets of mallards and american wigeon wintering in east-central Alabama
Author(s): Richard E. Turnbull AND Guy A. Baldassarre
Abstract: Mallards (Anas platyrhynchos) and American Wigeon ..[more]..
Source: Wilson Bull., 99(3), 1987, pp. 457464

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Title AMERICAN WIGEON MORTALITY ASSOCIATED WITH
TURF APPLICATION OF DIAZINON AG500
Author(s): . J. Kendall, L. W. Brewer, R. R. Hitchcock, and J. R. Mayer
Abstract: Nine fairways of a golf course located in Bellingh..[more]..
Source: Journal of Wildlife Diseases, 28(2), 1992. pp. 26.3-267

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Title Preliminary Overview of American Wigeon (Anas americana) Population Survey and Harvest Information ? An Atlantic Flyway Emphasis
Author(s): Doug Howell and Walt Rhodes
Abstract: Characterized by a haunting whistle and contrastin..[more]..
Source: Atlantic Flyway Council Technical Section

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Title Spatial and temporal use of estuary and upland habitats by
wintering waterfowl on the Fraser River delta and north Puget
Sound.
Author(s): Kate Hagmeier et al
Abstract: The Fraser River delta and north Puget Sound (FRDN..[more]..
Source: Proceedings of the 2005 Puget Sound Georgia Basin Research Conference

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