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121-537: The favorable mixture of lakes and surrounding irrigated croplands, combined with generally mild winters and protection provided by the refuge, attracts large numbers of migrating and wintering mallard ducks , Canada geese , trumpeter swans and tundra swans . Mammals species that inhabit this refuge include raccoon , mink , badger , elk , coyote , skunk , Canadian lynx , two species of deer , bobcat , beaver , porcupine , river otter , muskrat , and cougar . Hunting and particularly fishing are popular in

242-591: 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. 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. This maternal vocalisation is highly attractive to their young. The repetition and frequency modulation of these quacks form

363-681: 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 . During the breeding season, both male and female mallards can become aggressive, driving off competitors to themselves or their mate by charging at them. 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

484-733: A ballast tank of a ship traveling from the temperate zone through tropical waters may experience temperature fluctuations as much as 20 °C. Heat challenges during transport may enhance the stress tolerance of species in their non-native range, by selecting for genotypes that will survive a second applied heat stress, such as increased ocean temperature in the founder population. Invasive species often exploit disturbances to an ecosystem ( wildfires , roads , foot trails ) to colonize an area. Large wildfires can sterilize soils, while adding nutrients . Invasive plants that can regenerate from their roots then have an advantage over natives that rely on seeds for propagation. Invasive species can affect

605-609: A brood of ducklings. Nesting sites are typically on the ground, hidden in vegetation where the female's speckled plumage serves as effective camouflage , 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. Egg clutches number 8–13 creamy white to greenish-buff eggs free of speckles. They measure about 58 mm (2.3 in) in length and 32 mm (1.3 in) in width. The eggs are laid on alternate days, and incubation begins when

726-492: A combination of hot temperatures and reduced water levels place mallards at an increased risk of contracting botulism , as these conditions are ideal for Clostridium botulinum to propagate, with the birds also more likely to come into contact with botulinum toxin produced by the bacteria. Outbreaks of botulism among mallard populations can lead to mass die-offs. The predation-avoidance behaviour of sleeping with one eye open, allowing one brain hemisphere to remain aware while

847-529: A darker crown and eye-stripe. Mallards, like other sexually-dimorphic birds, can sometimes go though spontaneous sex reversal, often caused by damaged or nonfunctioning sex organs, such as the ovaries in mallard hens. 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

968-505: A few blood vessels to prevent heat loss, and, as in the Greenland mallard, the bill is smaller than that of birds farther south, illustrating the rule. 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 ). The mallard

1089-669: A few metres deep. They are attracted to bodies of water with aquatic vegetation. The mallard is omnivorous and very flexible in its choice of food. 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 . The majority of the mallard's diet seems to be made up of gastropods , insects (including beetles, flies, lepidopterans , dragonflies , and caddisflies ), crustaceans , other arthropods , worms, feces of other birds, many varieties of seeds and plant matter, and roots and tubers . During

1210-589: A few of the traits, and that noninvasive species had these also. Common invasive species traits include fast growth and rapid reproduction , such as vegetative reproduction in plants; association with humans; and prior successful invasions. Domestic cats are effective predators; they have become feral and invasive in places such as the Florida Keys . An introduced species might become invasive if it can outcompete native species for resources. If these species evolved under great competition or predation , then

1331-404: A glass window. This paper was awarded an Ig Nobel Prize in 2003. Mallards are opportunistically targeted by brood parasites , occasionally having eggs laid in their nests by redheads , ruddy ducks , lesser scaup , gadwalls , northern shovellers , northern pintails , cinnamon teal , common goldeneyes , and other mallards. These eggs are generally accepted when they resemble the eggs of

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1452-680: A great decrease in the population size and may constrict genetic variation , the individuals begin to show additive variance as opposed to epistatic variance. This conversion can lead to increased variance in the founding populations, which permits rapid evolution . Selection may then act on the capacity to disperse as well as on physiological tolerance to new stressors in the environment, such as changed temperature and different predators and prey. Rapid adaptive evolution through intraspecific phenotypic plasticity, pre-adaptation and post-introduction evolution lead to offspring that have higher fitness. Critically, plasticity permits changes to better suit

1573-470: A habitat in ways advantageous to other species. For example, zebra mussels increase habitat complexity on lake floors, providing crevices in which invertebrates live. This increase in complexity, together with the nutrition provided by the waste products of mussel filter-feeding , increases the density and diversity of benthic invertebrate communities. Introduced species may spread rapidly and unpredictably. When bottlenecks and founder effects cause

1694-543: A long taproot , or to live on previously uninhabited soil types. For example, barbed goatgrass was introduced to California on serpentine soils , which have low water-retention, low nutrient levels, a high magnesium / calcium ratio, and possible heavy metal toxicity. Plant populations on these soils tend to show low density, but goatgrass can form dense stands on these soils and crowd out native species. Invasive species might alter their environment by releasing chemical compounds, modifying abiotic factors, or affecting

1815-403: A major role in exotic species introduction. High demand for the valuable Chinese mitten crab is one explanation for the possible intentional release of the species in foreign waters. Maritime trade has rapidly affected the way marine organisms are transported within the ocean; new means of species transport include hull fouling and ballast water transport. In fact, Molnar et al. 2008 documented

1936-447: 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. Mallards are also preyed upon by other waterside apex predators , such as grey herons ( Ardea cinerea ), great blue herons ( Ardea herodias ) and black-crowned night herons ( Nycticorax nycticorax ),

2057-674: A new nomenclature system based on biogeography rather than on taxa . By discarding taxonomy, human health , and economic factors, this model focused only on ecological factors. The model evaluated individual populations rather than entire species. It classified each population based on its success in that environment. This model applied equally to indigenous and to introduced species, and did not automatically categorize successful introductions as harmful. The USDA's National Invasive Species Information Center defines invasive species very narrowly. According to Executive Order 13112, " 'Invasive species' means an alien species whose introduction does or

2178-407: A number of years and then experience an explosion in population, a phenomenon known as "the lag effect". Hybrids resulting from invasive species interbreeding with native species can incorporate their genotypes into the gene pool over time through introgression . Similarly, in some instances a small invading population can threaten much larger native populations. For example, Spartina alterniflora

2299-554: A particular pest species could pollute soil and surface water. Encroachment of humans into previously remote ecosystems has exposed exotic diseases such as HIV to the wider population. Introduced birds (e.g. pigeons ), rodents and insects (e.g. mosquito , flea , louse and tsetse fly pests) can serve as vectors and reservoirs of human afflictions. Throughout recorded history, epidemics of human diseases, such as malaria , yellow fever , typhus , and bubonic plague , spread via these vectors. A recent example of an introduced disease

2420-418: A result of either a numerical or fitness advantage of the introduced species. Genetic pollution occurs either through introduction or through habitat modification, where previously isolated species are brought into contact with the new genotypes. Invading species have been shown to adapt to their new environments in a remarkably short amount of time. The population size of invading species may remain small for

2541-527: 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". 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. At this time she is left by the male who joins up with other males to await

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2662-441: A separate subspecies, the Greenland mallard ( A.   p.   conboschas ). 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), and weighs 0.7–1.6 kg (1.5–3.5 lb). Among standard measurements,

2783-432: A sequence of 2-10 quacks in a row, starting loud and with the volume gradually decreasing. 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

2904-522: A severe threat to indigenous waterfowl's genetic integrity. Mallards and their hybrids compete with indigenous birds for resources, including nest sites, roosting sites, and food. 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

3025-747: A strong flavour. 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 . 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. Because of this, mallards have been found to be contaminated with

3146-418: A very small and fluctuating population. 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. However, these hybrids are less well adapted to the peculiar ecological conditions of Laysan Island than the local ducks, and thus have lower fitness . Laysan ducks were found throughout

3267-506: A white square on the wings in flight, and is a smaller bird. 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, 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

3388-721: Is 50–65 cm (20–26 in) long, of which the body makes up around two-thirds the length. The wingspan is 81–98 cm (32–39 in) and the bill is 4.4 to 6.1 cm (1.7 to 2.4 in) long. It is often slightly heavier than most other dabbling ducks, weighing 0.7–1.6 kg (1.5–3.5 lb). Mallards live in wetlands , eat water plants and small animals, and are social animals preferring to congregate in groups or flocks of varying sizes. The female lays 8 to 13 creamy white to greenish-buff spotless eggs , on alternate days. Incubation takes 27 to 28 days and fledging takes 50 to 60 days. The ducklings are precocial and fully capable of swimming as soon as they hatch. The mallard

3509-626: Is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of invasion. For millennia, humans have served as both accidental and deliberate dispersal agents, beginning with their earliest migrations , accelerating in the Age of Discovery , and accelerating again with international trade . Notably invasive plant species include the kudzu vine, giant hogweed , Japanese knotweed , and yellow starthistle . Notably invasive animals include European rabbits , domestic cats , and carp . Invasive species are

3630-488: Is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions , causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food web . Since the 20th century, invasive species have become serious economic, social, and environmental threats worldwide. Invasion of long-established ecosystems by organisms

3751-667: Is considered to be a species of least concern by the International Union for Conservation of Nature (IUCN). Unlike many waterfowl, mallards are considered an invasive species in some regions. It is a very adaptable species, being able to live and even thrive in urban areas which may have supported more localised, sensitive species of waterfowl before development. The non-migratory mallard interbreeds with indigenous wild ducks of closely related species through genetic pollution by producing fertile offspring. Complete hybridisation of various species of wild duck gene pools could result in

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3872-471: Is currently introgressing into the mallard populations of the Primorsky Krai , possibly due to habitat changes from global warming . The Mariana mallard was a resident allopatric population – in most respects a good species – apparently initially derived from mallard-Pacific black duck hybrids; it became extinct in the late 20th century. The Laysan duck is an insular relative of the mallard, with

3993-456: Is highly fire-adapted. It spreads rapidly after burning, and increases the frequency and intensity of fires by providing large amounts of dry detritus during the fire season in western North America. Where it is widespread, it has altered the local fire regimen so much that native plants cannot survive the frequent fires, allowing it to become dominant in its introduced range. Ecological facilitation occurs where one species physically modifies

4114-623: Is likely to cause economic or environmental harm or harm to human health." Typically, an introduced species must survive at low population densities before it becomes invasive in a new location. At low population densities, it can be difficult for the introduced species to reproduce and maintain itself in a new location, so a species might reach a location multiple times before it becomes established. Repeated patterns of human movement, such as ships sailing to and from ports or cars driving up and down highways, offer repeated opportunities for establishment (a high propagule pressure ). In ecosystems ,

4235-420: Is more a consequence of local ducks declining than of mallards spreading; allopatric speciation and isolating behaviour have produced today's diversity of mallard-like ducks despite the fact that, in most, if not all, of these populations, hybridisation must have occurred to some extent. Mallards are causing severe "genetic pollution" to South Africa's biodiversity by breeding with endemic ducks even though

4356-600: Is normal, and preserves constellations of genes and genotypes. An example of this is the interbreeding of migrating coyotes with the red wolf , in areas of eastern North Carolina where the red wolf was reintroduced, reducing red wolf numbers. In South Africa's Cape Town region, analysis demonstrated that the restoration of priority source water sub-catchments through the removal of thirsty alien plant invasions (such as Australian acacias, pines and eucalyptus, and Australian black wattle) would generate expected annual water gains of 50 billion liters within 5 years compared to

4477-635: Is not warranted a vulnerable rating. Also, the population size of the mallard is very large. Unlike many waterfowl, mallards have benefited from human alterations to the world – so much so that they are now considered an invasive species in some regions. They are a common sight in urban parks, lakes, ponds, and other human-made water features in the regions they inhabit, and are often tolerated or encouraged in human habitat due to their placid nature towards humans and their beautiful and iridescent colours. While most are not domesticated, mallards are so successful at coexisting in human regions that

4598-581: Is now considered invasive in over 60 countries, and has invaded large geographies in several countries prompting aggressive federal efforts at attempting to control it. Primary geomorphological effects of invasive plants are bioconstruction and bioprotection. For example, kudzu ( Pueraria montana ), a vine native to Asia, was widely introduced in the southeastern United States in the early 20th century to control soil erosion . The primary geomorphological effects of invasive animals are bioturbation , bioerosion , and bioconstruction. For example, invasions of

4719-479: Is one of the most problematic invasive plant species in eastern North American forests, where it is highly invasive of the understory , reducing the growth rate of tree seedlings and threatening to modify the forest's tree composition. Native species can be threatened with extinction through the process of genetic pollution . Genetic pollution is unintentional hybridization and introgression , which leads to homogenization or replacement of local genotypes as

4840-520: Is sometimes still used this way. It was derived from the Old French malart or mallart for "wild drake" although its true derivation is unclear. 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". Masle (male) has also been proposed as an influence. Mallards frequently interbreed with their closest relatives in

4961-626: Is somewhat shallow where the birds can be found foraging for food. Hunting mallards might cause the population to decline in some places, at some times, and with some populations. 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. Invasive species An invasive species

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5082-510: Is the main cause of introductions – other than for polar regions . Diseases may be vectored by invasive insects: the Asian citrus psyllid carries the bacterial disease citrus greening . The arrival of invasive propagules to a new site is a function of the site's invasibility. Many invasive species, once they are dominant in the area, become essential to the ecosystem of that area, and their removal could be harmful. Economics plays

5203-587: Is the spread of the West Nile virus , which killed humans, birds, mammals, and reptiles. The introduced Chinese mitten crabs are carriers of Asian lung fluke . Waterborne disease agents, such as cholera bacteria ( Vibrio cholerae ), and causative agents of harmful algal blooms are often transported via ballast water. Globally, invasive species management and control are substantial economic burdens, with expenditures reaching approximately $ 1.4 trillion annually. The economic impact of invasive alien species alone

5324-584: Is to prevent hybridisation with the native mottled duck . The mallard is considered an invasive species in Australia and New Zealand, where it competes with the Pacific black duck (known as the grey duck locally in New Zealand) which was over-hunted in the past. There, and elsewhere, mallards are spreading with increasing urbanisation and hybridising with local relatives. The eastern or Chinese spot-billed duck

5445-686: Is widely distributed across the Northern and Southern Hemispheres; in North America its range extends from southern and central Alaska to Mexico, the Hawaiian Islands , across the Palearctic , from Iceland and southern Greenland and parts of Morocco ( North Africa ) in the west, Scandinavia and Britain to the north, and to Siberia, Japan, and South Korea. Also in the east, it ranges to south-eastern and south-western Australia and New Zealand in

5566-575: 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. The hybrids of mallards and the yellow-billed duck are fertile, capable of producing hybrid offspring. If this continues, only hybrids occur and in the long term result in the extinction of various indigenous waterfowl. The mallard can crossbreed with 63 other species, posing

5687-766: 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 . 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 . Mallards are differentiated in their mitochondrial DNA between North American and Eurasian populations, but

5808-579: The European herring gull ( Larus argentatus ), the wels catfish ( Silurus glanis ), and the northern pike ( Esox lucius ). Crows ( Corvus   spp. ) are also known to kill ducklings and adults on occasion. Also, mallards may be attacked by larger anseriformes such as swans ( Cygnus   spp. ) and geese during the breeding season, and are frequently driven off by these birds over territorial disputes. Mute swans ( Cygnus olor ) have been known to attack or even kill mallards if they feel that

5929-516: The Great Lakes via ballast water. These outcompete native organisms for oxygen and food, and can be transported in the small puddle left in a supposedly empty ballast tank. Regulations attempt to mitigate such risks, not always successfully. Climate change is causing an increase in ocean temperature . This in turn will cause range shifts in organisms, which could harm the environment as new species interactions occur. For example, organisms in

6050-811: The Old World mallards and the New World mallard demonstrates the extent to which the genome is shared among them such that birds like the Chinese spot-billed duck are highly similar to the Old World mallard, and birds such as the Hawaiian duck are highly similar to the New World mallard. 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

6171-620: The United States Fish and Wildlife Service . Mallard duck A. p. platyrhynchos Linnaeus, 1758 A. p. domesticus Linnaeus, 1758 A. p. conboschas C. L. Brehm , 1831 (disputed) [REDACTED] The mallard ( / ˈ m æ l ɑːr d , ˈ m æ l ər d / ) or wild duck ( Anas platyrhynchos ) is a dabbling duck that breeds throughout the temperate and subtropical Americas , Eurasia , and North Africa . It has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, Colombia,

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6292-591: The economic returns from invasive species are far less than the costs they impose. In the Great Lakes region the sea lamprey is an invasive species. In its original habitat, it had co-evolved as a parasite that did not kill its host. However, in the Great Lakes Region, it acts as a predator and can consume up to 40 pounds of fish in its 12–18 month feeding period. Sea lampreys prey on all types of large fish such as lake trout and salmon . The sea lampreys' destructive effects on large fish negatively affect

6413-844: The extinction of species, loss in biodiversity, and loss of ecosystem services , costs from impacts of invasive species would drastically increase. It is often argued that the key to invasive species management is early detection and rapid response. However, early response only helps when the invasive species is not frequently reintroduced into the managed area, and the cost of response is affordable. Weeds reduce yield in agriculture . Many weeds are accidental introductions that accompany imports of commercial seeds and plants. Introduced weeds in pastures compete with native forage plants, threaten young cattle (e.g., leafy spurge, Euphorbia virgata ) or are unpalatable because of thorns and spines (e.g., yellow starthistle ). Forage loss from invasive weeds on pastures amounts to nearly US$ 1 billion in

6534-770: The genus Anas , such as the American black duck , and also with species more distantly related, such as the northern pintail , leading to various hybrids that may be fully fertile. The mallard has hybridised with more than 40 species in the wild, and an additional 20 species in captivity, though fertile hybrids typically have two Anas parents. Mallards and their domestic conspecifics are fully interfertile; many wild mallard populations in North America contain significant amounts of domestic mallard DNA. Genetic analysis has shown that certain mallards appear to be closer to their Indo-Pacific relatives, while others are related to their American relatives. Mitochondrial DNA data for

6655-744: The spatial scale of invasion studies. Small-scale studies tended to show a negative relationship between diversity and invasion, while large-scale studies tended to show the reverse, perhaps a side-effect of invasives' ability to capitalize on increased resource availability and weaker species interactions that are more common when larger samples are considered. However, this pattern does not seem to hold true for invasive vertebrates. Island ecosystems may be more prone to invasion because their species face few strong competitors and predators, and because their distance from colonizing species populations makes them more likely to have "open" niches. For example, native bird populations on Guam have been decimated by

6776-402: 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). The breeding male mallard is unmistakable, with a glossy bottle-green head and a white collar that demarcates the head and neck from the purple-tinged brown breast, grey-brown wings, and a pale grey belly. The rear of

6897-467: The 958 endangered species under the Endangered Species Act are at risk. The unintentional introduction of forest pest species and plant pathogens can change forest ecology and damage the timber industry . Overall, forest ecosystems in the U.S. are widely invaded by exotic pests, plants, and pathogens. The Asian long-horned beetle ( Anoplophora glabripennis ) was first introduced into

7018-518: The California sea otter ( Enhydra lutris ). Invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species . In some cases, the competition is about rates of growth and reproduction. In other cases, species interact with each other more directly. One study found that 86% of invasive species could be identified from such traits alone. Another study found that invasive species often had only

7139-493: The Chinese mitten crab ( Eriocheir sinensis ) have resulted in higher bioturbation and bioerosion rates. A native species can become harmful and effectively invasive to its native environment after human alterations to its food web . This has been the case with the purple sea urchin ( Strongylocentrotus purpuratus ), which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator,

7260-472: The Falkland Islands, and South Africa. This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae . Males (drakes) have green heads, while the females (hens) have mainly brown-speckled plumage . Both sexes have an area of white-bordered black or iridescent purple or blue feathers called a speculum on their wings; males especially tend to have blue speculum feathers. The mallard

7381-402: The Greenland mallard which is larger than the mallards further south. Allen's Rule says that appendages like ears tend to be smaller in polar forms to minimise heat loss, and larger in tropical and desert equivalents to facilitate heat diffusion, and that the polar taxa are stockier overall. Examples of this rule in birds are rare as they lack external ears, but the bill of ducks is supplied with

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7502-509: The Hawaiian archipelago before 400   AD, after which they suffered a rapid decline during the Polynesian colonisation. Now, their range includes only Laysan Island. It is one of the successfully translocated birds, after having become nearly extinct in the early 20th century. 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

7623-516: The Southern hemisphere. It is strongly migratory in the northern parts of its breeding range, and winters farther south. For example, in North America, it winters south to the southern United States and northern Mexico , but also regularly strays into Central America and the Caribbean between September and May. A drake later named "Trevor" attracted media attention in 2018 when it turned up on

7744-466: The U.S. A decline in pollinator services and loss of fruit production has been caused by honey bees infected by the invasive varroa mite . Introduced rats ( Rattus rattus and R. norvegicus ) have become serious pests on farms, destroying stored grains. The introduction of leaf miner flies ( Agromyzidae ), including the American serpentine leaf miner ( Liriomyza trifolii ), to California has caused losses in California's floriculture industry, as

7865-544: The U.S. in 1996, and was expected to infect and damage millions of acres of hardwood trees. As of 2005 thirty million dollars had been spent in attempts to eradicate this pest and protect millions of trees in the affected regions. The woolly adelgid has inflicted damage on old-growth spruce, fir and hemlock forests and damages the Christmas tree industry. Chestnut blight and Dutch elm disease are plant pathogens with serious impacts. Garlic mustard, Alliaria petiolata ,

7986-591: The alteration in ecosystem functionality (due to homogenization of biota communities), invasive species have resulted in negative effects on human well-being, which includes reduced resource availability, unrestrained spread of human diseases, recreational and educational activities, and tourism. Alien species have caused diseases including human immunodeficiency virus (HIV), monkey pox , and severe acute respiratory syndrome (SARS). Invasive species and accompanying control efforts can have long term public health implications. For instance, pesticides applied to treat

8107-496: The ancestors of Equus ferus (modern horses) evolved in North America and radiated to Eurasia before becoming extinct in North America. Upon being introduced to North America in 1493 by Spanish conquistadors , it is debatable whether the feral horses were native or exotic to the continent of their evolutionary ancestors. While invasive species can be studied within many subfields of biology, most research on invasive organisms has been in ecology and biogeography . Much of

8228-460: The annual summer moult. Upon hatching, the plumage of the duckling is yellow on the underside and face (with streaks by the eyes) and black on the back (with some yellow spots) all the way to the top and back of the head. Its legs and bill are also black. 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. Two months after hatching,

8349-535: The auditory basis for species identification in offspring, a process known as acoustic conspecific identification. In addition, females hiss if the nest or offspring are threatened or interfered with. When taking off, the wings of a mallard produce a characteristic faint whistling noise. The mallard is a rare example of both Allen's Rule and Bergmann's Rule in birds. Bergmann's Rule, which states that polar forms tend to be larger than related ones from warmer climates, has numerous examples in birds, as in case of

8470-478: The availability of resources determines the impact of additional species on the ecosystem. Stable ecosystems have a resource equilibrium, which can be changed fundamentally by the arrival of invasive species. When changes such as a forest fire occur, normal ecological succession favors native grasses and forbs . An introduced species that can spread faster than natives can outcompete native species for food, squeezing them out. Nitrogen and phosphorus are often

8591-408: The beginning and the end of the summer moulting period. The adulthood age for mallards is fourteen months, and the average life expectancy is three years, but they can live to twenty. Several species of duck have brown-plumaged females that can be confused with the female mallard. The female gadwall ( Mareca strepera ) has an orange-lined bill, white belly, black and white speculum that is seen as

8712-467: The behaviour of herbivores , impacting on other species. Some, like Kalanchoe daigremontana , produce allelopathic compounds that inhibit competitors. Others like Stapelia gigantea facilitate the growth of seedlings of other species in arid environments by providing appropriate microclimates and preventing herbivores from eating seedlings. Changes in fire regimens are another form of facilitation. Bromus tectorum , originally from Eurasia,

8833-400: 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. Plants generally make up the larger part of a bird's diet, especially during autumn migration and in

8954-507: The business-as-usual scenario (which is important as Cape Town experiences significant water scarcity ). This is the equivalent to one-sixth of the city's current supply needs. These annual gains will double within 30 years. The catchment restoration is significantly more cost-effective then other water augmentation solutions (1/10 the unit cost of alternative options). A water fund has been established, and these exotic species are being eradicated. Invasive species can affect human health. With

9075-455: The centre tail feather (drake feather) is curled, but in females, the centre tail feather is straight. During the final period of maturity leading up to adulthood (6–10 months of age), the plumage of female juveniles remains the same while the plumage of male juveniles gradually changes to its characteristic colours. This change in plumage also applies to adult mallard males when they transition in and out of their non-breeding eclipse plumage at

9196-841: The clutch is almost complete. Incubation takes 27–28   days and fledging takes 50–60   days. The ducklings are precocial and fully capable of swimming as soon as they hatch. 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. 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. 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 ,

9317-511: The densities of native forage plants, declining the habitat-use by wild herbivores and threatening the long-term sustenance of dependent carnivores, including the tiger . Invasive species can change the functions of ecosystems. For example, invasive plants can alter the fire regime (cheatgrass, Bromus tectorum ), nutrient cycling (smooth cordgrass Spartina alterniflora ), and hydrology ( Tamarix ) in native ecosystems. Invasive species that are closely related to rare native species have

9438-475: The ducks pose a threat to their offspring. Common loons ( Gavia inmer ) are similarly territorial and aggressive towards other birds in such disputes, and will frequently drive mallards away from their territory. 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. In summer,

9559-436: The expense to monitor, control, manage, and research invasive weed species is approximately AU$ 116.4 million per year, with costs directed solely to central and local government. While in some cases, invasive species may offer economic benefits, such as the potential for commercial forestry from invasive trees, these benefits are generally overshadowed by the substantial costs associated with biological invasions. In most cases,

9680-436: The extinction of many indigenous waterfowl. The mallard itself is the ancestor of most domestic ducks, and its naturally evolved wild gene pool gets genetically polluted in turn by the domestic and feral populations. Over time, a continuum of hybrids ranging between almost typical examples of either species develop; the speciation process is beginning to reverse itself. This has created conservation concerns for relatives of

9801-463: The extinction of many indigenous waterfowl. This species is the main ancestor of most breeds of domestic duck , and its naturally evolved wild gene pool has been genetically polluted by the domestic and feral mallard populations. The mallard was one of the many bird species originally described in the 1758 10th   edition of Systema Naturae by Carl Linnaeus . He gave it two binomial names : Anas platyrhynchos and Anas boschas . The latter

9922-423: The female. Lebret (1961) calls this behaviour "Attempted Rape Flight", and Stanley Cramp and K.E.L. Simmons (1977) speak of "rape-intent flights". Male mallards also occasionally chase other male ducks of a different species, and even each other, in the same way. 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

10043-563: The field lacks any official designation but is commonly referred to as "invasion ecology" or more generally "invasion biology". This lack of standard terminology has arisen due to the interdisciplinary nature of the field which borrows terms from disciplines such as agriculture , zoology , and pathology , as well as due to studies being performed in isolation. In an attempt to avoid the ambiguous, subjective, and pejorative vocabulary that so often accompanies discussion of invasive species even in scientific papers, Colautti and MacIsaac proposed

10164-629: The fishing industry and have helped cause the collapse of the population of some species. Economic costs from invasive species can be separated into direct costs through production loss in agriculture and forestry, and management costs. Estimated damage and control costs of invasive species in the U.S. amount to more than $ 138 billion annually. Economic losses can occur through loss of recreational and tourism revenues. When economic costs of invasions are calculated as production loss and management costs, they are low because they do not consider environmental damage; if monetary values were assigned to

10285-414: The fledgling period has ended, and the duckling is now a juvenile. The duckling is able to fly 50–60 days after hatching. Its bill soon loses its dark grey colouring, and its sex can finally be distinguished visually by three factors: 1)   the bill is yellow in males, but black and orange in females; 2)   the breast feathers are reddish-brown in males, but brown in females; and 3)   in males,

10406-408: The flock to begin fighting. It is possible that this behaviour allows the female to evaluate the strength of potential partners. 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

10527-402: The genes of the domestic duck. While the keeping of domestic breeds is more popular, pure-bred mallards are sometimes kept for eggs and meat, although they may require wing clipping to restrict flying. Mallards are one of the most common species shot in waterfowl hunting due to their large population size. The ideal location for hunting mallards is considered to be where the water level

10648-446: The governments of California and New Zealand have announced more stringent control for vessel hull fouling within their respective jurisdictions. Another vector of non-native aquatic species is ballast water taken up at sea and released in port by transoceanic vessels. Some 10,000 species are transported via ballast water each day. Many of these are harmful. For example, freshwater zebra mussels from Eurasia most likely reached

10769-420: The host mallard, but the hen may attempt to eject them or even abandon the nest if parasitism occurs during egg laying. 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 raptors and owls , mustelids , corvids , snakes , raccoons , opossums , skunks , turtles , large fish , felids , and canids ,

10890-489: The individual to its environment. Pre-adaptations and evolution after the introduction reinforce the success of the introduced species. The enemy release hypothesis states that evolution leads to ecological balance in every ecosystem. No single species can occupy a majority of an ecosystem due to the presences of competitors, predators, and diseases. Introduced species moved to a novel habitat can become invasive, with rapid population growth, when these controls do not exist in

11011-518: The introductions of the amethyst gem clam and the European green crab . The gem clam was introduced into California's Bodega Harbor from the US East Coast a century ago. On its own, it never displaced native clams ( Nutricola spp.). In the mid-1990s, the introduction of the European green crab resulted in an increase of the amethyst gem at the expense of the native clams. In India, multiple invasive plants have invaded 66% of natural areas, reducing

11132-538: The invaded habitats and bioregions adversely, causing ecological, environmental, or economic damage. The European Union defines "Invasive Alien Species" as those that are outside their natural distribution area, and that threaten biological diversity . Biotic invasion is one of the five top drivers for global biodiversity loss , and is increasing because of tourism and globalization . This may be particularly true in inadequately regulated fresh water systems, though quarantines and ballast water rules have improved

11253-646: The invasive brown tree snake . In New Zealand the first invasive species were the dogs and rats brought by Polynesian settlers around 1300. These and other introductions devastated endemic New Zealand species. The colonization of Madagascar brought similar harm to its ecosystems. Logging has caused harm directly by destroying habitat, and has allowed non-native species such as prickly pear and silver wattle to invade. The water hyacinth forms dense mats on water surfaces, limiting light penetration and hence harming aquatic organisms, and causing substantial management costs. The shrub lantana ( Lantana camara )

11374-503: The island of Niue , an atypical location for mallards. The mallard inhabits a wide range of habitats and climates, from the Arctic tundra to subtropical regions. 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. Water depths of less than 0.9 metres (3.0 ft) are preferred, with birds avoiding areas more than

11495-472: The last two including domestic cats and dogs. The most prolific natural predators of adult mallards are red foxes ( Vulpes vulpes ; which most often pick off brooding females) and the faster or larger birds of prey, (e.g. peregrine falcons , Aquila or Haliaeetus eagles). 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

11616-443: The limiting factors in these situations. Every species occupies an ecological niche in its native ecosystem; some species fill large and varied roles, while others are highly specialized. Invading species may occupy unused niches, or create new ones. For example, edge effects describe what happens when part of an ecosystem is disturbed, as when land is cleared for agriculture . The boundary between remaining undisturbed habitat and

11737-734: The main conservation risk they pose comes from the loss of genetic diversity among a region's traditional ducks once humans and mallards colonise an area. Mallards are very adaptable, being able to live and even thrive in urban areas which may have supported more localised, sensitive species of waterfowl before development. The release of feral mallards in areas where they are not native sometimes creates problems through interbreeding with indigenous waterfowl . These non-migratory mallards interbreed with indigenous wild ducks from local populations of closely related species through genetic pollution by producing fertile offspring. Complete hybridisation of various species of wild duck gene pools could result in

11858-447: The male is black, with white-bordered dark tail feathers. 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. 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

11979-488: The mallard species. Ecological changes and hunting have also led to a decline of local species; for example, the New Zealand grey duck population declined drastically due to overhunting in the mid-20th century. Hybrid offspring of Hawaiian ducks seem to be less well adapted to native habitat, and using them in re-introduction projects apparently reduces success. In summary, the problems of mallards "hybridising away" relatives

12100-539: The mallard, such as the Hawaiian duck , the New Zealand grey duck ( A.   s. superciliosa) subspecies of the Pacific black duck , the American black duck, the mottled duck , Meller's duck , the yellow-billed duck , and the Mexican duck , in the latter case even leading to a dispute as to whether these birds should be considered a species (and thus entitled to more conservation research and funding) or included in

12221-474: The moulting period, which begins in June (in the Northern Hemisphere). 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) or forcibly mate with females that appear to be isolated or unattached regardless of their species and whether or not they have

12342-444: 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. 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

12463-630: The new ecosystem. Non-native species have many vectors , but most are associated with human activity. Natural range extensions are common, but humans often carry specimens faster and over greater distances than natural forces. An early human vector occurred when prehistoric humans introduced the Pacific rat ( Rattus exulans ) to Polynesia. Vectors include plants or seeds imported for horticulture . The pet trade moves animals across borders, where they can escape and become invasive. Organisms stow away on transport vehicles. Incidental human assisted transfer

12584-523: The new environment may host fewer able competitors, allowing the invader to proliferate. Ecosystems used to their fullest capacity by native species can be modeled as zero-sum systems, in which any gain for the invader is a loss for the native. However, such unilateral competitive superiority (and extinction of native species with increased populations of the invader) is not the rule. An invasive species might be able to use resources previously unavailable to native species, such as deep water accessed by

12705-528: The newly cleared land itself forms a distinct habitat, creating new winners and losers and possibly hosting species that would not thrive outside the boundary habitat. In 1958, Charles S. Elton claimed that ecosystems with higher species diversity were less subject to invasive species because fewer niches remained unoccupied. Other ecologists later pointed to highly diverse, but heavily invaded ecosystems, arguing that ecosystems with high species diversity were more susceptible to invasion. This debate hinged on

12826-479: The nuclear genome displays a notable lack of genetic structure. Haplotypes typical of American mallard relatives and eastern spot-billed ducks can be found in mallards around the Bering Sea . The Aleutian Islands hold a population of mallards that appear to be evolving towards becoming a subspecies , as gene flow with other populations is very limited. Also, the paucity of morphological differences between

12947-503: The other half sleeps, was first demonstrated in mallards, although it is believed to be widespread among birds in general. Since 1998, the mallard has been rated as a species of least concern on the IUCN Red List of Endangered Species . This is because it has a large range–more than 20,000,000 km (7,700,000 mi ) and because its population is increasing, rather than declining by 30% over ten years or three generations and thus

13068-703: The park. Hunting is only allowed at certain times on certain days and seasons and requires a permit. The refuge is located in the rainshadow of the Cascade Mountains, and the climate is arid and desert -like. The park receives less than eight inches of annual rainfall on average. The wildlife is supported by water routed from the Grand Coulee Dam , and the park is part of the Columbia Basin Project . [REDACTED]  This article incorporates public domain material from websites or documents of

13189-476: The pathways of hundreds of marine invasive species and found that shipping was the dominant mechanism for the transfer of invasive species. Many marine organisms can attach themselves to vessel hulls. Such organisms are easily transported from one body of water to another, and are a significant risk factor for a biological invasion event. Controlling for vessel hull fouling is voluntary and there are no regulations currently in place to manage hull fouling. However,

13310-525: The point of visiting water features in human courtyards . 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, 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. Domestic ducks are mostly kept for meat; their eggs are also eaten, and have

13431-464: The potential to hybridize with the native species. Harmful effects of hybridization have led to a decline and even extinction of native species. For example, hybridization with introduced cordgrass, Spartina alterniflora , threatens the existence of California cordgrass ( Spartina foliosa ) in San Francisco Bay . Invasive species cause competition for native species and because of this 400 of

13552-412: The situation. Invasive species may drive local native species to extinction via competitive exclusion, niche displacement, or hybridisation with related native species. Therefore, besides their economic ramifications, alien invasions may result in extensive changes in the structure, composition and global distribution of the biota at sites of introduction, leading ultimately to the homogenisation of

13673-406: The speculum. In captivity, domestic ducks come in wild-type plumages, white, and other colours. 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. A noisy species, the female has the deep quack stereotypically associated with ducks. The female will often call with

13794-495: The spread of biological invasions, mitigate further impacts, and restore affected ecosystems. For example, the damage caused by 79 invasive species between 1906 and 1991 in the United States has been estimated at US$ 120 billion. Similarly, in China , invasive species have been reported to reduce the country's gross domestic product (GDP) by 1.36% per year. The management of biological invasions can be costly. In Australia , for instance,

13915-711: The subset of established non-native alien or naturalized species that are a threat to native species and biodiversity. The term "invasive" is poorly defined and often very subjective. Invasive species may be plants, animals, fungi, and microbes; some include native species that have invaded human habitats such as farms and landscapes. Some broaden the term to include indigenous or "native" species that have colonized natural areas. Some sources name Homo sapiens as an invasive species, but broad appreciation of human learning capacity and their behavioral potential and plasticity may argue against any such fixed categorization. The definition of "native" can be controversial. For example,

14036-482: The winter. The mallard usually feeds by dabbling for plant food or grazing; there are reports of it eating frogs , other amphibians , and fish , including carcasses . 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. It usually nests on

14157-502: The work has been influenced by Charles Elton's 1958 book The Ecology of Invasion by Animals and Plants which creates a generalized picture of biological invasions. Studies remained sparse until the 1990s. This research, largely field observational studies, has disproportionately been concerned with terrestrial plants . The rapid growth of the field has driven a need to standardize the language used to describe invasive species and events. Despite this, little standard terminology exists;

14278-405: The world's fauna and flora and the loss of biodiversity . It is difficult to unequivocally attribute extinctions to a species invasion, though there is for example strong evidence that the extinction of about 90 amphibian species was caused by the chytrid fungus spread by international trade. Multiple successive introductions of different non-native species can worsen the total effect, as with

14399-416: Was estimated to exceed $ 423 billion annually as of 2019. This cost has exhibited a significant increase, quadrupling every decade since 1970, underscoring the escalating financial implications of these biological invasions. Invasive species contribute to ecological degradation , altering ecosystem functionality and reducing the services ecosystems provide. This necessitates additional expenditures to control

14520-519: Was generally preferred until 1906 when Einar Lönnberg established that A.   platyrhynchos had priority, as it appeared on an earlier page in the text. The scientific name comes from Latin Anas , "duck" and Ancient Greek πλατυρυγχος, platyrhynchus , "broad-billed" (from πλατύς, platys , "broad" and ρυγχός, rhunkhos , "bill"). The genome of Anas platyrhynchos was sequenced in 2013. The name mallard originally referred to any wild drake, and it

14641-462: Was introduced in the San Francisco Bay and hybridized with native Spartina foliosa . The higher pollen count and male fitness of the invading species resulted in introgression that threatened the native populations due to lower pollen counts and lower viability of the native species. Reduction in fitness is not always apparent from morphological observations alone. Some degree of gene flow

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