The gadwall (Mareca strepera) is a widespread dabbling duck in the family Anatidae. This species is closely related to the Falcated duck and its scientific name "strepera" means "noisy".
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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HerbivoreA herbivore is an animal anatomically and physiologically adapted to eating plant material, for example, foliage, for the main component of its die...
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FolivoreIn zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less ...
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GranivoreSeed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of pla...
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GraminivoreIn zoology, a graminivore (not to be confused with a granivore) is an herbivorous animal that feeds primarily on grass. Graminivory is a form of g...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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WaterfowlWaterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans. They ...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
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Serial monogamySerial monogamy is a mating system in which a pair bonds only for one breeding season.
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FlockingFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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starts withThe male gadwall is slightly larger than the female. 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. In non-breeding (eclipse) plumage, the drake looks more like the female but retains the male wing pattern, is usually greyer above, and has less orange on the bill. 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, white speculum, and white belly. Both sexes go through two molts annually, following a juvenile molt.
Gadwalls breed in the northern areas of Europe and across the Palearctic, and central North America. In North America, they are found 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. Gadwalls are strongly migratory, and winter from coastal Alaska, south into Central America, and east into Idaho, Kansas, Ohio, Virginia, and then south all the way into Central America. In Great Britain, gadwalls are scarce-breeding birds and winter visitors, though their population has increased in recent years. In Ireland, a small breeding population has recently become established, centered on County Wexford in the south and Lough Neagh in the north. Gadwalls are also seen in some parts of South Asia, particularly the southern part of India. These ducks prefer to live in open wetlands, such as prairie or steppe lakes, wet grassland, or marshes with dense fringing vegetation.
Gadwalls are not very gregarious and usually form only small flocks. They are diurnal birds that usually feed by dabbling for plant food with head submerged. They can also dive underwater for food, more proficiently than other dabbling ducks, and may also steal food from diving birds such as coots. Gadwalls are generally quiet ducks, except during their courtship display. Females give a call similar to the quack of a female mallard but higher-pitched, described as ‘gag-ag-ag-ag’. Males give a grunt, that sounds like ‘mep’, and a whistle. Gadwalls may also warn each other by lifting their chin or opening their bill at another bird.
Gadwalls are mostly herbivores (folivores, granivores, graminivores) and eat a big variety of aquatic vegetation including leaves, roots, stems, grasses, and seeds. During the winter time, they may supplement their diet with a small amount of animal matter such as insects, beetles, mollusks, amphibians, small fish, and snails. The ducklings feed on insects at first.
Gadwalls are serially monogamous and form pairs that remain together for only one breeding season. Pair formation begins during fall migration or on breeding grounds, but has also been reported to occur in August when males are still in eclipse plumage. During a courtship display known as the burp the male utters a ‘mep’ call; he raises his head pointing his bill towards a female. The grunt-whistle is similar to that of mallards, where the male rears his outstretched head with the bill dipped into water, displacing a stream of water droplets towards a nearby female as the bill is raised against the chest. During this display, the male makes a loud whistle call followed by a low burp. Paired males may follow other females in flight displays. Gadwalls nests on the ground, often some distance from water. Pairs nest singly or in small groups. The female scrapes out a hollow in the ground and lines it with her plucked down feathers. She lays 7 to 12 eggs and incubates them for about 24-27 days. The duckling hatch fully developed (precocial), with eyes open, covered with down, and ready to leave the nest within a few days. After hatching the female will move her young to more sheltered areas further from the nesting site. Young gadwalls may start breeding after their first year of age.
Gadwalls suffer from disturbances, pollution, nest predation, lead shot ingestion in some areas, and hunting.
According to IUCN Red List, the total population size of the gadwall is around 4,300,000-4,900,000 individuals. The European population consists of 75,400-125,000 pairs, which equates to 151,000-250,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...