Ruddy duck | |
---|---|
Male | |
Female | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Anseriformes |
Family: | Anatidae |
Genus: | Oxyura |
Species: | O. jamaicensis |
Binomial name | |
Oxyura jamaicensis (Gmelin, 1789) | |
Extant, breeding Extant, resident Extant, passage Extant, non-breeding Extant & Introduced (resident) Probably extinct | |
Synonyms | |
Erismatura jamaicensis |
The ruddy duck (Oxyura jamaicensis) is one duck of six species within the stiff-tailed ducks (Oxyura). They occupy heavily vegetated habitats in North and South America as well as the British Isles, France and Spain. Ruddy ducks were introduced to the United Kingdom in the 1940s where they have since established a growing population. Outside the Americas, ruddy ducks are considered a highly invasive species, prompting many countries to initiate culling projects to eradicate them from the native ecosystem.
The genus name is derived from Ancient Greek oxus, "sharp", and oura, "tail", and jamaicensis is "from Jamaica". Ruddy ducks have also been nicknamed “butterball”, a term used to describe an individual who is somewhat fat, due to their short and stout stature making activities like flying and walking upright awkward. [2]
The ruddy duck was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae . He placed it with the other ducks, geese and swans in the genus Anas and coined the binomial name Anas jamaicensis. [3] Gmelin based his description on the "Jamaica shoveler" that had been described in 1785 by the English ornithologist John Latham from a specimen that he had received from Jamaica. [4] The ruddy duck is now placed with five other species in the genus Oxyura that was introduced in 1828 by the French naturalist Charles Lucien Bonaparte. [5] [6] The genus name is derived from Ancient Greek oxus, meaning "sharp", and oura meaning "tail". The specific epithet jamaicensis means "from Jamaica". [7] The Andean duck was formerly considered to be conspecific with the ruddy duck but with the two species split, the ruddy duck is monotypic: no subspecies are recognised. [6]
These are small, compact ducks with stout, scoop-shaped bills, and long, stiff tails they often hold cocked upward. They have slightly peaked heads and fairly short, thick necks. Male ruddy ducks have blackish caps that contrast with bright white cheeks. In summer, they have rich chestnut bodies with bright blue bills. In winter, they are dull gray-brown above and paler below with dull gray bills. Females and first-year males are brownish, somewhat like winter males but with a blurry stripe across the pale cheek patch. In flight, ruddy ducks show solidly dark tops of the wings. [8] On average, females are smaller and weigh less than males.
They have a short and stout scoop-shaped bill designed for underwater foraging. With their short stature, they are known to be great swimmers whilst finding taking flight a much more laboured task. [9] In comparison to other ducks, ruddy ducks rarely fly but when they do, it is done with a very fast wingbeat and closely over the water. [10]
An interesting physical feature found within this taxonomy of duck is the trachea and stiff-tails’s inflatable air sacs and esophagi which are used in displays. [11] The tail of the ruddy duck is commonly seen held upwards. [12]
Standard Measurements [13] [14] | |
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Total Body Length | 340–430 mm (13.5–17 in) |
Weight | 560 g (1.23 lb) |
Wingspan | 470 mm (18.5 in) |
Wing | 133–147.5 mm (5.24–5.81 in) |
Tail | 67–79 mm (2.6–3.1 in) |
Culmen | 38.5–41 mm (1.52–1.61 in) |
Tarsus | 33–38 mm (1.3–1.5 in) |
Both male and female ruddy ducks are not known to be very vocal most of the year, though they do become more vocal when courting and raising young. [11] Males are known to produce short “aa-anh” calls and other noises in short bursts. Female ruddy ducks have a much higher pitched call, often having a “raanh” sound when communicating with their brood, squeaks when chased by males, and hisses and nasal sounds towards intruders. [2]
Unlike other migratory anatine courtship where partnerships occur in wintering grounds, ruddy ducks often begin courtship on the breeding ground. Both male and female ruddy ducks have been observed interacting aggressively with each other but despite aggression, pairs can be seen loafing next to each other minutes later. [15] Their breeding habitat is marshy lakes and ponds.
Both male and females are not known to be very vocal with quacks, though males are known to produce a distinct drumming sound by beating their lower mandible on their breast. This drumming beat is done hard enough that often swirls of bubbles will appear in the water. This display is known as “bubbling”. [10]
In an aggressive response, the male faces his rival while performing bubbling. In courting, a bubbling male orientates his body laterally to the female. In a group of courting birds of more than one male, the males typically display rapidly alternating forms of bubbling in accordance with constantly and suddenly changing aggressive and sexual responses. [15]
Females do not do much stimulation in courting gestures and mostly respond to the male’s advances. [10]
They nest in dense marsh vegetation near water. The female builds the nest out of grass, locating it in tall vegetation to hide it from predators. A typical brood contains 5 to 15 ducklings. [16] Pairs form each year. Though ruddy ducks can have large broods, the male normally takes no part in rearing. [15] The female will incubate the eggs for 23-26 days whilst being protected by her mate. [2] After the young hatch, it only takes about a month or two until they are fully ready to fly but as a result of the young being independent very quickly, they often stray from the rest of the brood. Females will care for her young but never for the entire period of the fledgling. [10]
Female ruddy ducks have been observed acting in brood parasitism. There hasn’t been a clear factor that influences females to lay their eggs in other nests. Though it was observed that parasitic eggs were more likely to be male than female hatchlings. [15] Though some suspect that the parasitic laying is directly tied to the lack of attunement between the female ruddy duck and the environmental cues. [17]
They are migratory and winter in coastal bays and unfrozen lakes and ponds.
Ruddy ducks mainly feed on a large amount of plant matter like seeds and roots as well as aquatic insects and crustaceans. A large portion of the animal matter consumed is larvae and pupae. [9] [18] During the winter, they often consume a higher amount of animal food.
The food foraged is done underwater, an activity that the ruddy duck excels at. They forage by straining food from the surface of the substrate, moving their bills side to side whilst opening and closing their mandibles. This allows their food to stay caught in between their bill whilst the substrate is filtered out.
Due to all foraging occurring with substrate clouding the water, the way ruddy ducks select their prey is not through visuals. Instead, ruddy ducks use tactile location of the larvae and pupae to forage. [19]
Ruddy ducks can also feed on small molluscs and crustaceans like bivalves and amphipods. They are able to find these organisms in moving waters by using the tip of their bill as it has many sensory endings which direct the duck towards their food. The slight crooked shape of their mandible also allows them to efficiently tear at plant matter underwater. [10]
When searching for randomly placed food patches, Ruddy Ducks sampled previously profitable sites before investigating other areas more frequently than would be expected by chance. Revisiting previously profitable foraging sites may be important when exploiting a patchy food resource with prey densities that are likely to be quickly replenished after having been exploited. [20]
As a result of escapes from wildfowl collections in the late 1950s, they became established in Great Britain, from where they spread into Europe. This duck's aggressive courting behavior and willingness to interbreed with the endangered native white-headed duck (Oxyura leucocephala), of southern Europe, caused concern amongst Spanish conservationists. Due to this, a controversial scheme to extirpate the ruddy duck as a British breeding species started; there have also been culling attempts in other European countries. [21]
By March 2012 a culling program in the UK, supported by the RSPB, had killed 6,500, at a cost of £5m (£769 per bird). [22] In 2003 the BBC had reported the cost of killing each bird at £915. [21] In 2012 Lee Evans, founder of the British Birding Association, claimed "The cull cannot succeed now. There are hundreds of ruddy ducks on the continent which will not be killed so the birds will continue to breed. There's never been any proof, anyway, that the British population has ever interbred with the Spanish ducks". [22] By early 2014, the cull had reduced the British population to about 20–100, down from a peak of about 5,500 in 2000. [23] According to Animal Aid, in the UK the cost of hunting down the last few ruddy ducks was £3,000 per bird. They advised "If you see one, don’t tell anyone. Even bird groups will tell the authorities and those birds may be killed". [24]
In Europe, the Ruddy duck is included since 2016 in the list of Invasive Alien Species of Union concern (the Union list). [25] This implies that this species cannot be imported, bred, transported, commercialized, or intentionally released into the environment in the whole of the European Union. [26]
The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating on the water surface, and, in some cases, diving in at least shallow water. The family contains around 174 species in 43 genera.
The stiff-tailed ducks, the genus Oxyura, are part of the Oxyurini tribe of ducks.
The gadwall is a common and widespread dabbling duck in the family Anatidae.
The redhead is a medium-sized diving duck. The scientific name is derived from Greek aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin americana, of America. The redhead is 40–56 cm (16–22 in) long with an 74–84 cm (29–33 in) wingspan; the weight ranges from 1,030–1,080 g (36–38 oz), with males weighing an average of 1,080 g (38 oz) and females an average of 1,030 g (36 oz). It belongs to the genus Aythya, together with 11 other described species. The redhead and the common pochard form a sister group which together is sister to the canvasback. This waterfowl is easily distinguished from most other ducks by the male's copper colored head and pale blue bill during the breeding season; from its close relative canvasback it is distinguished by the more rounded head, shorter bill, and yellow, not red, eye. The Eurasian common pochard is even more similar, but very rarely overlaps in range; it also differs in having a red eye, and a more acute, less rounded head shape.
The common pochard, known simply as pochard in the United Kingdom, is a medium-sized diving duck in the family Anatidae. It is widespread across the Palearctic. It breeds primarily in the steppe regions of Scandinavia and Siberia, and winters further south and west.
The mandarin duck is a perching duck species native to the East Palearctic. It is sexually dimorphic, with males showing a dramatic difference from the females. It is medium-sized, at 41–49 cm (16–19 in) long with a 65–75 cm (26–30 in) wingspan. It is closely related to the North American wood duck, the only other member of the genus Aix. 'Aix' is an Ancient Greek word which was used by Aristotle to refer to an unknown diving bird, and 'galericulata' is the Latin for a wig, derived from galerum, a cap or bonnet. Outside of its native range, the mandarin duck has a large introduced population in the British Isles and Western Europe, with additional smaller introductions in North America.
Barrow's goldeneye is a medium-sized sea duck of the genus Bucephala, the goldeneyes. This bird was named after Sir John Barrow. The genus name is derived from Ancient Greek boukephalos, "bullheaded", from bous, "bull" and kephale, "head", a reference to the bulbous head shape of the bufflehead. The species name islandica means Iceland.
The bufflehead is a small sea duck of the genus Bucephala, the goldeneyes. It breeds in Alaska and Canada and migrates in winter to southern North America. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Anas albeola.
The American coot, also known as a mud hen or pouldeau, is a bird of the family Rallidae. Though commonly mistaken for ducks, American coots are only distantly related to ducks, belonging to a separate order. Unlike the webbed feet of ducks, coots have broad, lobed scales on their lower legs and toes that fold back with each step to facilitate walking on dry land. Coots live near water, typically inhabiting wetlands and open water bodies in North America. Groups of coots are called covers or rafts. The oldest known coot lived to be 22 years old.
The cotton pygmy goose or cotton teal is a small perching duck which breeds in Asia, Southeast Asia extending south and east to Queensland where they are sometimes called white-quilled pygmy goose. They are among the smallest waterfowl in the world and are found in small to large waterbodies with good aquatic vegetation. They are usually seen in pairs or larger groups of pairs, roosting and nesting on trees near water. They are strong fliers and are known to disperse widely, especially in winter. Their breeding season coincides with the rains.
The black-headed duck is a South American duck in subfamily Oxyurinae of family Anatidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.
The white-headed duck is a small diving duck some 45 cm (18 in) long. The male has a white head with black crown, a blue bill, and reddish-grey plumage. The female has a dark bill and rather duller colouring. Its breeding habitat is lakes with open water and dense vegetation at the margin. It dives under water and feeds on aquatic vegetation as well as some animal matter. It is more likely to swim away from a perceived threat than to fly. This duck is known from Spain, North Africa, Western Asia and Central Asia. Populations are declining, mostly due to loss of habitat and pollution, and the International Union for Conservation of Nature has rated the bird's status as "endangered".
The blue duck or whio is a member of the duck, goose and swan family Anatidae endemic to New Zealand. It is the only member of the genus Hymenolaimus. Its exact taxonomic status is still unresolved, but it appears to be most closely related to the tribe Anatini, the dabbling ducks.
The paradise shelduck, also known as the paradise duck, or pūtangitangi in Māori, is a species of shelduck, a group of goose-like ducks, which is endemic to New Zealand. Johann Friedrich Gmelin placed it in the genus Anas with the ducks, geese, and swans. Both the male and female have striking plumages: the male has a black head and barred black body and the female has a white head with a chestnut body. They weigh between 1.09 and 2 kg and are between 63 and 71 cm in length.
The red-billed teal or red-billed duck is a dabbling duck which is an abundant resident breeder in southern and eastern Africa typically south of 10° S. This duck is not migratory, but will fly great distances to find suitable waters. It is highly gregarious outside the breeding season and forms large flocks.
The lake duck is a small, South American stiff-tailed duck. It is also called the Argentine blue-bill, Argentine blue-billed duck, Argentine lake duck, or Argentine ruddy duck.
The blue-billed duck is a small Australian stiff-tailed duck, with both the male and female growing to a length of 40 cm (16 in). The male has a slate-blue bill which changes to bright-blue during the breeding season, hence the duck's common name. The male has deep chestnut plumage during breeding season, reverting to a dark grey. The female retains black plumage with brown tips all year round. The duck is endemic to Australia's temperate regions, inhabiting natural inland wetlands and also artificial wetlands, such as sewage ponds, in large numbers. It can be difficult to observe due to its cryptic nature during its breeding season through autumn and winter. The male duck exhibits a complex mating ritual. The blue-billed duck is omnivorous, with a preference for small aquatic invertebrates. BirdLife International has classified this species as Least concern. Major threats include drainage of deep permanent wetlands, or their degradation as a result of introduced fish, peripheral cattle grazing, salinization, and lowering of ground water.
The Maccoa duck is a stiff-tailed diving duck found across Eastern and Southern Africa.
The South Georgia pintail, also misleadingly known as the South Georgian teal, is the nominate subspecies of the yellow-billed pintail, a duck in the dabbling duck subfamily Anatinae. It is endemic to the large (3,756 km2) subantarctic island of South Georgia and its accompanying archipelago, and is a vagrant to the South Sandwich Islands. It was among the birds noted by James Cook in January 1775, on the occasion of the first recorded landing on South Georgia, and was formerly considered a full species.
The Andean duck is a bird species native to the Andean Mountains of South America, one of the stiff-tailed ducks. It was considered a subspecies of the ruddy duck. In fact, some taxonomic authorities still consider it conspecific, including the American Ornithological Society.