[order] ANSERIFORMES | [family] Anatidae | [latin] Anas crecca | [authority] Linnaeus, 1758 | [UK] Eurasian Teal | [FR] Sarcelle de hiver | [DE] Krickente | [ES] Cerceta comun | [NL] Wintertaling
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. 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. 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.
Male Green-winged Teal have a dark grey body with a russet head, and a large, dark-green eye-patch extending to its nape. Females are light mottled brown with a dark eye-line characteristic of all dabbler females. When breeding, both sexes have a white belly that is conspicuous in flight and a vibrant dark-green speculum with buff borders; often the only obvious color visible
Listen to the sound of Eurasian Teal
Copyright remark: Most sounds derived from xeno-canto
Eurasia : widespread
Green-winged Teal prefer wooded ponds but can also be found in deciduous wooded ponds surrounded by grassy upland areas. During migration, both spring and fall, green-wings tend to choose shallow inland wetlands with abundant floating and emergent vegetation, but also use tidal mudflats more often than any other duck. Wintering Greenwings will use freshwater shallow marshes and riparian sloughs, but can also be found in saltwater estuaries and agricultural areas.
Greenwings form pair ponds relatively late in the season compared with other dabbling ducks, often not until late January all the way to March. Although they break their pair bond each year, Greenwings are monogamous throughout the breeding season; however, occasionally paired males will attempt forced extra-pair copulations with other females. After an elaborate sequence of displays, the female will show her approval by performing her inciting display next to her mate of choice. Once the pair is ready to mate, they will perform some reciprocated head pumping, and then will copulate on the water. Nesting females will choose an area to nest that is well concealed, with thick brush, sedge or grasses. Nesting females will choose an area to nest that is well concealed, with thick brush, sedge or grasses. She will often scrape out an area or choose a depression on the ground to construct a nest bowl by using surrounding grasses, twigs and leaves. Like other ducks, the female will also use her body feathers to aid in keeping the eggs warm, dry and concealed. The surrounding vegetation will usually form a type of canopy, concealing the nest from predators. In most cases, a female will lay one egg per day until the clutch is complete, usually 10-12 eggs. Shortly after incubation begins, the male will abandon his mate and begin to moult. During this process, he will shed his breeding plumage into a drab, hen-like plumage and remain flightless for several weeks, until growing back into his breeding plumage in preparation for fall migration and another breeding season.
The female, meanwhile, will incubate her eggs for approximately 3 weeks after her last egg is laid. Once her ducklings have hatched, she moves them to water within the first day, where the precocial young will be reared. Often ducklings are unable to maintain a high body temperature when first hatched, and the female will continue to brood during wet and cold periods.
The Green-winged Teals diet is very diverse, relying on insects and aquatic vegetation. An opportunistic feeder, the Greenwing varies its diet according to what is most abundant at the time. Vegetation is eaten mostly in the fall and winter, consisting mainly of seeds of grasses, sedge and emergent vegetation, as well as the occasional agricultural crop. During the breeding season, Greenwings rely more on animal matter such as aquatic insects, larvae, mollusks, crustaceans and sometimes fish eggs. A true dabbler, Greenwings often feed by tipping-up with their head under the surface of the water or collecting seeds and insects by skimming the water with its bill. More than any other duck, Greenwings will feed along mud flats, foraging for seeds, insects and mollusks.
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 is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds 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 nominate race of this duck inhabits northern Eurasia and the carolinensis race North America. For practical reasons, the European populations can be divided in two sub-populations, separated mainly by their wintering quarters. The first, estimated at 400000 individuals and undergoing a definite increase, is wintering along the Atlantic coasts from Denmark to the British Isles and Aquitaine. During very strong winters it reaches Spain and Portugal, but in mild winters the birds of the Netherlands and the British Isles are almost sedentary. The second population is estimated at 750000-1375000 individuals, but its trends are unknown. It winters in the Black Sea region and around the Mediterranean. Only a small fraction of these birds is reaching West Africa
Partially migratory, northernmost breeding birds descending to lower latitudes in winter, as far S as equator (Kenya), but breeders of more temperate regions present throughout year.