Mallard

It has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, Colombia, the Falkland Islands, and South Africa.The non-migratory mallard interbreeds with indigenous wild ducks of closely related species through genetic pollution by producing fertile offspring.[5] The scientific name comes from Latin Anas, "duck" and Ancient Greek πλατυρυγχος, platyrhynchus, "broad-billed" (from πλατύς, platys, "broad" and ρυγχός, rhunkhos, "bill").[9] It may be related to, or at least influenced by, an Old High German masculine proper name Madelhart, clues lying in the alternative English forms "maudelard" and "mawdelard".[18] The large Ice Age palaeosubspecies that made up at least the European and West Asian populations during the Pleistocene has been named Anas platyrhynchos palaeoboschas.[19]Mallards are differentiated in their mitochondrial DNA between North American and Eurasian populations,[20] but the nuclear genome displays a notable lack of genetic structure.[31] This phenomenon can cause female mallards to exhibit male plumage, and vice versa (phenotypic feminisation or masculinisation).Both male and female mallards have distinct iridescent purple-blue speculum feathers edged with white, which are prominent in flight or at rest but temporarily shed during the annual summer moult.[33] As it nears a month in age, the duckling's plumage starts becoming drab, looking more like the female, though more streaked, and its legs lose their dark grey colouring.[43] Most of these colour variants are also known in domestic mallards not bred as livestock, but kept as pets, aviary birds, etc., where they are rare but increasing in availability.[45][46] When incubating a nest, or when offspring are present, females vocalise differently, making a call that sounds like a truncated version of the usual quack.[68] It is found in both fresh- and salt-water wetlands, including parks, small ponds, rivers, lakes and estuaries, as well as shallow inlets and open sea within sight of the coastline.[73] The majority of the mallard's diet seems to be made up of gastropods,[74] insects (including beetles, flies, lepidopterans, dragonflies, and caddisflies),[75] crustaceans,[76] other arthropods,[77] worms,[74] feces of other birds,[78] many varieties of seeds and plant matter,[74] and roots and tubers.The mallard usually feeds by dabbling for plant food or grazing; there are reports of it eating frogs, other amphibians, and fish, including carcasses.[82][78] However, in 2017 a flock of mallards in Romania were observed hunting fledglings of small migratory birds when they land in the water, which included a grey wagtail and a black redstart.[84] Mallards usually form pairs (in October and November in the Northern Hemisphere) until the female lays eggs at the start of the nesting season, which is around the beginning of spring.[95] However, filial imprinting compels them to instinctively stay near the mother, not only for warmth and protection but also to learn about and remember their habitat as well as how and where to forage for food.[96] Though adoptions are known to occur, female mallards typically do not tolerate stray ducklings near their broods, and will violently attack and drive away any unfamiliar young, sometimes going as far as to kill them.[98] In cases where a nest or brood fails, some mallards may mate for a second time in an attempt to raise a second clutch, typically around early-to-mid summer.[100] Males tend to fight more than females and attack each other by repeatedly pecking at their rival's chest, ripping out feathers and even skin on rare occasions.[108] In North America, adult mallards face no fewer than 15 species of birds of prey, from northern harriers (Circus hudsonius) and short-eared owls (Asio flammeus) (both smaller than a mallard) to huge bald (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos), and about a dozen species of mammalian predators, not counting several more avian and mammalian predators who threaten eggs and nestlings.Mute swans (Cygnus olor) have been known to attack or even kill mallards if they feel that the ducks pose a threat to their offspring.[113] However, in 2019, a pair of common loons in Wisconsin were observed raising a mallard duckling for several weeks, having seemingly adopted the bird after it had been abandoned by its parents.[119][121] These non-migratory mallards interbreed with indigenous wild ducks from local populations of closely related species through genetic pollution by producing fertile offspring.[126] Hybrid offspring of Hawaiian ducks seem to be less well adapted to native habitat, and using them in re-introduction projects apparently reduces success.[124] The eastern or Chinese spot-billed duck is currently introgressing into the mallard populations of the Primorsky Krai, possibly due to habitat changes from global warming.[22] The Mariana mallard was a resident allopatric population – in most respects a good species – apparently initially derived from mallard-Pacific black duck hybrids;[139] it became extinct in the late 20th century.[141][1] Mallards sometimes arrive on its island home during migration, and can be expected to occasionally have remained and hybridised with Laysan ducks as long as these species have existed.[149] While the keeping of domestic breeds is more popular, pure-bred mallards are sometimes kept for eggs and meat,[150] although they may require wing clipping to restrict flying.[153] Since standardized data collection began in 1990, the United States Federal Aviation Administration has recorded 1320 mallard collisions with aircraft, 261 of which caused damage to the craft (through 2022).