Mallard
Mallard Temporal range:
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Female (left) and male (right) in Straßlach-Dingharting, Germany | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Anseriformes |
Family: | Anatidae |
Genus: | Anas |
Species: | A. platyrhynchos
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Binomial name | |
Anas platyrhynchos Linnaeus, 1758
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Subspecies | |
A. p. platyrhynchos Linnaeus, 1758 | |
Range of A. platyrhynchos Breeding Resident Passage Non-breeding Vagrant (seasonality uncertain) Possibly extant and introduced Extant and introduced (seasonality uncertain) Possibly extant and introduced (seasonality uncertain)
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Synonyms | |
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The mallard (
The female lays 8 to 13 creamy white to greenish-buff spotless
The mallard is considered to be a
Taxonomy and evolutionary history
The mallard was one of the many bird species originally described in the 1758 10th edition of Systema Naturae by Carl Linnaeus.[2] He gave it two binomial names: Anas platyrhynchos and Anas boschas.[3] The latter was generally preferred until 1906 when Einar Lönnberg established that A. platyrhynchos had priority, as it appeared on an earlier page in the text.[4] The scientific name comes from Latin Anas, "duck" and Ancient Greek πλατυρυγχος, platyrhynchus, "broad-billed" (from πλατύς, platys, "broad" and ρυγχός, rhunkhos, "bill").[5] The genome of Anas platyrhynchos was sequenced in 2013.[6]
The name mallard originally referred to any wild drake, and it is sometimes still used this way.[7] It was derived from the Old French malart or mallart for "wild drake" although its true derivation is unclear.[8] 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".[9] Masle (male) has also been proposed as an influence.[10]
Mallards frequently interbreed with their closest relatives in the
Genetic analysis has shown that certain mallards appear to be closer to their Indo-Pacific relatives, while others are related to their American relatives.[16] Mitochondrial DNA data for the D-loop sequence suggest that mallards may have evolved in the general area of Siberia. Mallard bones rather abruptly appear in food remains of ancient humans and other deposits of fossil bones in Europe, without a good candidate for a local predecessor species.[17] 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.[18]
Mallards are differentiated in their mitochondrial DNA between North American and Eurasian populations,
Also, the paucity of
The size of the mallard varies clinally; for example, birds from Greenland, though larger, have smaller bills, paler plumage, and stockier bodies than birds further south and are sometimes classified as a separate subspecies, the Greenland mallard (A. p. conboschas).[23]
Description
The mallard is a medium-sized waterfowl species that is often slightly heavier than most other dabbling ducks. It is 50–65 cm (20–26 in) long – of which the body makes up around two-thirds – has a wingspan of 81–98 cm (32–39 in),[24]: 505 and weighs 0.7–1.6 kg (1.5–3.5 lb).[25] Among standard measurements, the wing chord is 25.7 to 30.6 cm (10.1 to 12.0 in), the bill is 4.4 to 6.1 cm (1.7 to 2.4 in), and the tarsus is 4.1 to 4.8 cm (1.6 to 1.9 in).[26] The breeding male mallard is unmistakable, with a glossy bottle-green head and a white collar that demarcates the head from the purple-tinged brown breast, grey-brown wings, and a pale grey belly.[27] The rear of the male is black, with white-bordered dark tail feathers.[24]: 506 The bill of the male is a yellowish-orange tipped with black, with that of the female generally darker and ranging from black to mottled orange and brown.[28] The female mallard is predominantly mottled, with each individual feather showing sharp contrast from buff to very dark brown, a coloration shared by most female dabbling ducks, and has buff cheeks, eyebrow, throat, and neck, with a darker crown and eye-stripe.[24]: 506 Mallards, like other sexually-dimorphic birds, can sometimes go though spontaneous sex reversal,[29] often caused by damaged or nonfunctioning sex organs, such as the ovaries in mallard hens.[30] 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.
Several species of duck have brown-plumaged females that can be confused with the female mallard.[37] The female gadwall (Mareca strepera) has an orange-lined bill, white belly, black and white speculum that is seen as a white square on the wings in flight, and is a smaller bird.[24]: 506 More similar to the female mallard in North America are the American black duck (A. rubripes), which is notably darker-hued in both sexes than the mallard,[38] and the mottled duck (A. fulvigula), which is somewhat darker than the female mallard, and with slightly different bare-part colouration and no white edge on the speculum.[38]
In captivity, domestic ducks come in wild-type plumages, white, and other colours.[42] 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.[42]
A noisy species, the female has the deep quack stereotypically associated with ducks.[24]: 507 Male mallards make a sound phonetically similar to that of the female, a typical quack, but it is deeper and quieter compared to that of the female. Research conducted by Middlesex University on two English mallard populations found that the vocalisations of the mallard varies depending on their environment and have something akin to a regional accent, with urban mallards in London being much louder and more vociferous compared to rural mallards in Cornwall, serving as an adaptation to persistent levels of anthropogenic noise.[43][44]
When
The mallard is a rare example of both
Due to the variability of the mallard's genetic code, which gives it its vast interbreeding capability, mutations in the genes that decide plumage colour are very common and have resulted in a wide variety of hybrids, such as Brewer's duck (mallard × gadwall, Mareca strepera).[51]
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Iridescent speculum feathers of the male
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Female showing pattern of the back and the coloured wing patches
Distribution and habitat
The mallard is widely distributed across the
The mallard inhabits a wide range of habitats and climates, from the Arctic tundra to subtropical regions.[66] 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.[67] Water depths of less than 0.9 metres (3.0 ft) are preferred, with birds avoiding areas more than a few metres deep.[68] They are attracted to bodies of water with aquatic vegetation.[24]: 507
Behaviour
Feeding
The mallard is omnivorous and very flexible in its choice of food.[70] Its diet may vary based on several factors, including the stage of the breeding cycle, short-term variations in available food, nutrient availability, and interspecific and intraspecific competition.[71] The majority of the mallard's diet seems to be made up of gastropods,[72] insects (including beetles, flies, lepidopterans, dragonflies, and caddisflies),[73] crustaceans,[74] other arthropods,[75] worms,[72] many varieties of seeds and plant matter,[72] and roots and tubers.[74] During the breeding season, male birds were recorded to have eaten 37.6% animal matter and 62.4% plant matter, most notably the grass Echinochloa crus-galli, and nonlaying females ate 37.0% animal matter and 63.0% plant matter, while laying females ate 71.9% animal matter and only 28.1% plant matter.[76] Plants generally make up the larger part of a bird's diet, especially during autumn migration and in the winter.[77][78]
The mallard usually feeds by dabbling for plant food or grazing; there are reports of it eating frogs.[79] However, in 2017 a flock of mallards in Romania were observed hunting small migratory birds, including grey wagtails and black redstarts, the first documented occasion they had been seen attacking and consuming large vertebrates.[80] It usually nests on a river bank, but not always near water. It is highly gregarious outside of the breeding season and forms large flocks, which are known as "sordes".[81]
Breeding
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.[82] At this time she is left by the male who joins up with other males to await the moulting period, which begins in June (in the Northern Hemisphere).[83][84] During the brief time before this, however, the males are still sexually potent and some of them either remain on standby to sire replacement clutches (for female mallards that have lost or abandoned their previous clutch)[85] or forcibly mate with females that appear to be isolated or unattached regardless of their species and whether or not they have a brood of ducklings.[85][86]
Nesting sites are typically on the ground, hidden in vegetation where the female's speckled plumage serves as effective camouflage,[87] but female mallards have also been known to nest in hollows in trees, boathouses, roof gardens and on balconies, sometimes resulting in hatched offspring having difficulty following their parent to water.[88]
Egg clutches number 8–13 creamy white to greenish-buff eggs free of speckles.
When ducklings mature into flight-capable juveniles, they learn about and remember their traditional migratory routes (unless they are born and raised in captivity). In New Zealand, where mallards are naturalised, the nesting season has been found to be longer, eggs and clutches are larger and nest survival is generally greater compared with mallards in their native range.[95]
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. In addition, mallards may occasionally breed during the autumn in cases of unseasonably warm weather; one such instance of a 'late' clutch occurred in November 2011, in which a female successfully hatched and raised a clutch of eleven ducklings at the London Wetland Centre.[96]
During the breeding season, both male and female mallards can become aggressive, driving off competitors to themselves or their mate by charging at them.[97] 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. Female mallards are also known to carry out 'inciting displays', which encourage other ducks in the flock to begin fighting.[98] It is possible that this behaviour allows the female to evaluate the strength of potential partners.[99]
The drakes that end up being left out after the others have paired off with mating partners sometimes target an isolated female duck, even one of a different species, and proceed to chase and peck at her until she weakens, at which point the males take turns copulating with the female.[100] Lebret (1961) calls this behaviour "Attempted Rape Flight", and Stanley Cramp and K.E.L. Simmons (1977) speak of "rape-intent flights".[100] Male mallards also occasionally chase other male ducks of a different species, and even each other, in the same way.[100] In one documented case of "homosexual necrophilia", a male mallard copulated with another male he was chasing after the chased male died upon flying into a glass window.[100] This paper was awarded an Ig Nobel Prize in 2003.[101]
Mallards are opportunistically targeted by
Predators and threats
In addition to human hunting, mallards of all ages (but especially young ones) and in all locations must contend with a wide diversity of predators including
Mallards are also preyed upon by other waterside
The predation-avoidance behaviour of sleeping with one eye open, allowing one brain hemisphere to remain aware while the other half sleeps, was first demonstrated in mallards, although it is believed to be widespread among birds in general.[112]
Status and conservation
Since 1998, the mallard has been rated as a species of
Unlike many waterfowl, mallards have benefited from human alterations to the world – so much so that they are now considered an
Invasiveness
Mallards are causing severe "genetic pollution" to South Africa's biodiversity by breeding with endemic ducks[130] even though the Agreement on the Conservation of African-Eurasian Migratory Waterbirds – an agreement to protect the local waterfowl populations – applies to the mallard as well as other ducks.[131] The hybrids of mallards and the yellow-billed duck are fertile, capable of producing hybrid offspring.[132] If this continues, only hybrids occur and in the long term result in the extinction of various indigenous waterfowl.[132] The mallard can crossbreed with 63 other species, posing a severe threat to indigenous waterfowl's genetic integrity.[133] Mallards and their hybrids compete with indigenous birds for resources, including nest sites, roosting sites, and food.[130]
Availability of mallards, mallard ducklings, and fertilised mallard eggs for public sale and private ownership, either as poultry or as pets, is currently legal in the United States, except for the state of Florida, which has currently banned domestic ownership of mallards. This is to prevent hybridisation with the native mottled duck.[134]
The mallard is considered an invasive species in Australia and New Zealand,
The eastern or
The
Relationship with humans
Domestication
Mallards have often been ubiquitous in their regions among the ponds, rivers, and streams of human parks, farms, and other human-made waterways – even to the point of visiting water features in human courtyards.[141]
Mallards have had a long relationship with humans. Almost all domestic duck breeds derive from the mallard, with the exception of a few Muscovy breeds,[142] and are listed under the trinomial name A. p. domesticus. Mallards are generally monogamous while domestic ducks are mostly polygamous. Domestic ducks have no territorial behaviour and are less aggressive than mallards.[143] Domestic ducks are mostly kept for meat; their eggs are also eaten, and have a strong flavour.[143] They were first domesticated in Southeast Asia at least 4,000 years ago, during the Neolithic Age, and were also farmed by the Romans in Europe, and the Malays in Asia.[144] As the domestic duck and the mallard are the same species as each other, it is common for mallards to mate with domestic ducks and produce hybrid offspring that are fully fertile.[145] Because of this, mallards have been found to be contaminated with the genes of the domestic duck.[145]
While the keeping of domestic breeds is more popular, pure-bred mallards are sometimes kept for eggs and meat,[146] although they may require wing clipping to restrict flying.
Hunting
Mallards are one of the most common varieties of ducks hunted as a sport due to the large population size. The ideal location for hunting mallards is considered to be where the water level is somewhat shallow where the birds can be found foraging for food.[147] Hunting mallards might cause the population to decline in some places, at some times, and with some populations.[148] In certain countries, the mallard may be legally shot but is protected under national acts and policies. For example, in the United Kingdom, the mallard is protected under the Wildlife and Countryside Act 1981, which restricts certain hunting methods or taking or killing mallards.[149]
As food
Since ancient times, the mallard has been eaten as food. The wild mallard was eaten in
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External links
- "Mallard media". Internet Bird Collection.
- Mallard photo gallery at VIREO (Drexel University)