Sunday, February 6, 2011

White-cheeked Pintail

The White cheeked Pintail or Bahama Pintail (Anas bahamensis) is a dabbling duck of the Caribbean, South America, and the Galápagos Islands.[2]
This species was first described by Linnaeus in his Systema naturae in 1758 under its current scientific name.[3] There are three subspecies: A. b. bahamensis in the Caribbean, and a vagrant in south Florida. A. b. galapagensis on the Galapagos, and the slightly larger A. b. rubirostris in South America. The latter race may be partially migratory, breeding in Argentina and wintering further north.[2]
Duck pato 005eue.jpgLike many southern ducks, the sexes are similar. It is mainly brown with white cheeks and a red-based grey bill (young birds lack the pink). It cannot be confused with any other duck in its range.[2]
This species occurs on waters with a degree of salinity, such as brackish lakes, estuaries and mangrove swamps.[2]
White.cheeked.pintail.750pix.jpgThe White-cheeked Pintail feeds on aquatic plants and small creatures obtained by dabbling. The nest is on the ground under vegetation and near water.[2]

Northern Pintail

The Pintail or Northern Pintail (Anas acuta) is a widely occurring duck which breeds in the northern areas of Europe, Asia and North America. It is strongly migratory and winters south of its breeding range to the equator. Unusually for a bird with such a large range, it has no geographical subspecies if the possibly con-specific Eaton's Pintail is considered to be a separate species.
This is a fairly large duck, with a long pointed tail that gives rise to the species' English and scientific names. The Northern Pintail's many names describe the male's two long black tail feathers, which in flight look like a single pin or twig (thus, the nickname sprig). These feathers are very distinctive, accounting for a quarter of the total length of the drake when in full plumage.[2] Fast and graceful fliers, pintails are equipped with long wings, small heads, and long necks that seem built for streamlined aerodynamics. Both sexes have blue gray bills and gray legs and feet. The drake is more striking, having a thin white stripe running from the back of its chocolate-colored head down its neck to its mostly white undercarriage. The drake also has attractive gray, brown, and black patterning on its back and sides. The hen's plumage is more subtle and subdued, with drab brown feathers similar to those of other female dabblers. Hens make a coarse quack and the drakes a flute-like whistle.[2]
The Northern Pintail is a bird of open wetlands which nests on the ground, often some distance from water. It feeds by dabbling for plant food and adds small invertebrates to its diet during the nesting season. It is highly gregarious when not breeding, forming large mixed flocks with other species of duck.
This duck's population is affected by predators, parasites and avian diseases. Human activities, such as agriculture, hunting and fishing, have also had a significant impact on numbers. Nevertheless, this species' huge range and large population mean that it is not threatened globally.
Taxonomy
This species was first described by Linnaeus in his Systema naturae in 1758 as Anas acuta[3] The scientific name comes from two Latin words: anas, meaning "duck", and acuta, which comes from the verb acuere, which means "sharpen"; the species term, like the English name, refers to the pointed tail of the male.[4]
Within the large dabbling duck genus Anas,[3] the Northern Pintail's closest relatives are other pintails, such as the Yellow-billed Pintail (A. georgica) and Eaton's Pintail (A. eatoni). The pintails are sometimes separated in the genus Dafila (described by Stephens, 1824), an arrangement supported by morphological, molecular and behavioural data.[5][6][7] The famous British ornithologist Sir Peter Scott gave this name to his daughter, the artist Dafila Scott.[8]
Eaton's Pintail has two subspecies, A. e. eatoni (the Kerguelen Pintail) of Kerguelen Islands, and A. e. drygalskyi (the Crozet Pintail) of Crozet Islands, and was formerly considered conspecific with the northern hemisphere's Northern Pintail. Sexual dimorphism is much less marked in the southern pintails, with the male's breeding appearance being similar to the female plumage. Unusually for a species with such a large range, Northern Pintail has no geographical subspecies if Eaton's Pintail is treated as a separate species.
 Description
The Northern Pintail is a fairly large duck with a wingspan of 23.6–28.2 centimetres (9.3–11.1 in). The male is 59–76 centimetres (23–30 in) in length and weighs 450–1360 grammes (1–3 lb), and therefore is considerably larger than the female, which is 51–64 centimetres (20–25 in) long and weighs 454–1135 grammes (1–2.5 lb).[10] The male in breeding plumage has a chocolate-brown head and white breast with a white stripe extending up the side of the neck. Its upperparts and sides are grey, but elongated grey feathers with black central stripes are draped across the back from the shoulder area. The vent area is yellow, contrasting with the black underside of the tail,[9] which has the central feathers elongated to as much as 10 centimetres (4 in). The bill is bluish and the legs are blue-grey.
The adult female is mainly scalloped and mottled in light brown with a more uniformly grey-brown head, and its pointed tail is shorter than the male’s; it is still easily identified by its shape, long neck, and long grey bill.
In non-breeding (eclipse) plumage, the drake Pintail looks similar to the female, but retains the male upperwing pattern and long grey shoulder feathers. Juvenile birds resemble the female, but are less neatly scalloped and have a duller brown speculum with a narrower trailing edge.[12]
The Pintail walks well on land, and swims buoyantly.[9] It has a very fast flight, with its wings slightly swept-back, rather than straight out from the body like other ducks. In flight, the male shows a black speculum bordered white at the rear and pale rufous at the front, whereas the female's speculum is dark brown bordered with white, narrowly at the front edge but very prominently at the rear, being visible at a distance of 1600 metres (1 mi).[12]
The male's call is a soft proop-proop whistle, similar to that of the Common Teal, whereas the female has a Mallard-like descending quack, and a low croak when flushed.[9]
Distribution and habitatThe Northern Pintail has been called the "nomads of the skies." due to their wide-ranging migrations.[2] This dabbling duck breeds across northern areas of Eurasia south to about Poland and Mongolia,[10] and in Canada, Alaska and the Midwestern United States. It winters mainly south of its breeding range, reaching almost to the equator in Panama, northern sub-Saharan Africa and tropical South Asia. Small numbers migrate to Pacific islands, particularly Hawaii, where a few hundred birds winter on the main islands in shallow wetlands and flooded agricultural habitats.[9] Transoceanic journeys also occur: a bird that was caught and ringed in Labrador, Canada, was shot by a hunter in England nine days later,[10] and Japanese-ringed birds have been recovered from six US states east to Utah and Mississippi.[13] In parts of the range, such as Great Britain and the northwestern United States, the Pintail may be present all year.[12][14][15]
The Northern Pintail's breeding habitat is open unwooded wetlands, such as wet grassland, lakesides or tundra. In winter, it will utilise a wider range of open habitats, such as sheltered estuaries, brackish marshes and coastal lagoons. It is highly gregarious outside the breeding season and forms very large mixed flocks with other ducks.[9]
Behaviour
 Breeding
Breeding pairBoth sexes reach sexual maturity at one year of age. The male mates with the female by swimming close to her with his head lowered and tail raised, continually whistling. If there is a group of males, they will chase the female in flight until only one drake is left. The female prepares for copulation, which takes place in the water, by lowering her body; the male then bobs his head up and down and mounts the female, taking the feathers on the back of her head in his mouth. After mating, he raises his head and back and whistles.[10]
Breeding takes place between April and June, with the nest being constructed on the ground and hidden amongst vegetation in a dry location, often some distance from water. It is a shallow scrape on the ground lined with plant material and down.[9] The female lays seven to nine cream-coloured eggs at the rate of one per day;[10] the eggs are 55 x 38 millimetres (2.2 x 1.5 in) in size and weigh 45 grammes (1.6 oz), of which 7% is shell.[16] If predators destroy the first clutch, the female can produce a replacement clutch as late as the end of July.[10]
The hen alone incubates the eggs for 22 to 24 days before they hatch. The precocial downy chicks are then led by the female to the nearest body of water, where they feed on dead insects on the water surface. The chicks fledge in 46 to 47 days after hatching, but stay with the female until she has completed moulting.[10]
Around three-quarters of chicks live long enough to fledge, but not more than half of those survive long enough to reproduce.[10] The maximum recorded age is 27 years and 5 months for a Dutch bird,[16] but the average life span for wild birds will be much shorter than this, and is likely to be similar to that of other wild ducks, such as the Mallard, at about two years.[17]
Feeding Up-ending to feed (male on right)The Pintail feeds by dabbling and upending in shallow water for plant food mainly in the evening or at night, and therefore spends much of the day resting.[9] Its long neck enables it to take food items from the bottom of water bodies up to 30 centimetres (1 ft) deep, which are beyond the reach of other dabbling ducks like the Mallard.[11]
The winter diet is mainly plant material including seeds and rhizomes of aquatic plants, but the Pintail sometimes feeds on roots, grain and other seeds in fields, though less frequently than other Anas ducks.[11] During the nesting season, this bird eats mainly invertebrate animals, including aquatic insects, molluscs and crustaceans.[10]
Health
Pintail nests and chicks are vulnerable to predation by mammals, such as foxes and badgers, and birds like gulls, crows and magpies. The adults can take flight to escape terrestrial predators, but nesting females in particular may be surprised by large carnivores such as bobcats.[10] Large birds of prey, such as Northern Goshawks, will take ducks from the ground, and some falcons, including the Gyrfalcon, have the speed and power to catch flying birds.[18]

Male preeningIt is susceptible to a range of parasites including Cryptosporidium, Giardia, tapeworms, blood parasites and external feather lice,[19][20][21][22] and is also affected by other avian diseases. It is often the dominant species in major mortality events from avian botulism and avian cholera,[23] and can also contract avian influenza, the H5N1 strain of which is highly pathogenic and occasionally infects humans.[24]
The Northern Pintail is a popular species for game shooting because of its speed, agility, and excellent eating qualities, and is hunted across its range.[25][26] Although one of the world's most numerous ducks,[16] the combination of hunting with other factors has led to population declines, and local restrictions on hunting have been introduced at times to help conserve numbers.[27]
This species' preferred habitat of shallow water is naturally susceptible to problems such as drought or the encroachment of vegetation, but this duck’s habitat might be increasingly threatened by climate change.[16] Populations are also affected by the conversion of wetlands and grassland to arable crops, depriving the duck of feeding and nesting areas. Spring planting means that many nests of this early breeding duck are destroyed by farming activities,[28] and a Canadian study showed that more than half of the surveyed nests were destroyed by agricultural work such as ploughing and harrowing.[29]

FemaleHunting with lead shot, along with the use of lead sinkers in angling, has been identified as a major cause of lead poisoning in waterfowl, which often feed off the bottom of lakes and wetlands where the shot collects.[30] A Spanish study showed that Northern Pintail and Common Pochard were the species with the highest levels of lead shot ingestion, higher than in northern countries of the western Palearctic flyway, where lead shot has been banned.[31] In the United States, Canada, and many western European countries, all shot used for waterfowl must now be non-toxic, and therefore may not contain any lead.[32][33][34]
Status
The Northern Pintail has a large range, estimated at 10 million square kilometres (0.4-3.8 million sq mi), and a population estimated at 6.1–7.7 million individuals. It is therefore not believed to meet the IUCN Red List threshold criterion of a population decline of more than 30% in ten years or three generations, and is evaluated as Least Concern.[1]

Feeding maleIn the Palaearctic, breeding populations are declining in much of the range, including its stronghold in Russia, and are otherwise stable or fluctuating.[35]
Pintails in North America at least have been badly affected by avian diseases, with the breeding population falling from more than 10 million in 1957 to 3.5 million by 1964. Although the species has recovered from that low point, the breeding population in 1999 was 30% below the long-term average, despite years of major efforts focused on restoring the species. In 1997, an estimated 1.5 million water birds, the majority being Northern Pintails, died from avian botulism during two outbreaks in Canada and Utah.[23]

Falcated Duck

The Falcated Duck or Falcated Teal (Anas falcata) is a Gadwall-sized dabbling duck
Taxonomy
The closest relative of this species is the Gadwall, followed by the wigeons.[2]
Distribution and habitat
The Falcated duck breeds in eastern Asia. It nests in eastern Russia, in Khabarovsk, Primorskiy, Amur, Chita, Buryatia, Irkutsk, Tuva, eastern Krasnoyarsk, south central Sakha Sakhalin, extreme northeastern North Korea and northern China, in northeastern Inner Mongolia, and northern Heilongjiang, and in northern Japan, Hokkaidō, Aomori, and the Kuril Islands[3]. It is widely recorded well outside its normal range, but the popularity of this beautiful duck in captivity clouds the origins of these extralimital birds.
This dabbling duck is strongly migratory and winters in much of Southeast Asia. In India: Uttar Pradesh, Bihār, Assam, eastern Haryāna. Also in northern Bangladesh, northern and central Myanmar, northern Laos to the Mekong River, northern Vietnam (from about Hanoi north), and China: Hainan, Taiwan, Yunnan, Guangxi Zhuang, Guangdong, Fujian, Jiangxi, northern Hunan, Hubei, Zhejiang, Anhui, Jiangsu, Shandong, southern Hebei, Shanxi, northern Shaanxi[3]. It is gregarious outside the breeding season and will then form large flocks.
This is a species of lowland wetlands, such as water meadows or lakes, and usually feeds by dabbling for plant food or grazing. It nests on the ground, near water and under the cover of taller vegetation. The clutch is 6–10 eggs.
Identification

This is a at 48–54 cm length. The breeding male is unmistakable. Most of the body plumage is finely vermiculated grey, with the long sickle-shaped tertials, which give this species its name, hanging off its back. The large head is dark green with a white throat, and a dark green collar and bronzed crown)[4]. The vent region is patterned in yellow, black and white.
The female Falcated Duck is dark brown, with plumage much like a female wigeon. Its long grey bill is an aid to identification[4]. The eclipse male is like the female, but darker on the back and head. In flight both sexes show a pale grey underwing. The blackish speculum is bordered with a white bar on its inner edge[4]. Young birds are buffer than the female and have short tertials.
The male Falcated Duck has a clear low whistle, whereas the female has a gruff "quack".

Gadwall

The Gadwall (Anas strepera) is a common and widespread duck of the family Anatidae. This species was first described by Linnaeus in his Systema naturae in 1758 under its current scientific name.[2]









Description
The Gadwall is 46–56 cm (18–22 in) long with a 78–90 cm (31–35 in) wingspan.[3] The male is slightly larger than the female, weighing on average 990 g (35 oz) against her 850 g (30 oz).[4] The breeding male is patterned grey, with a black rear end, light chestnut wings, and a brilliant white speculum, obvious in flight or at rest.[5] In non-breeding (eclipse) plumage, the drake looks more like the female, but retains the male wing pattern, and is usually greyer above and has less orange on the bill.[4]
The female is light brown, with plumage much like a female Mallard. It can be distinguished from that species by the dark orange-edged bill, smaller size, the white speculum, and white belly.[5] Both sexes go through two moults annually, following a juvenile moult.[3]
The Gadwall is a quieter duck, except during its courtship display. Females give a call similar to the quack of a female Mallard but higher-pitched, transcribed as gag-ag-ag-ag. Males give a grunt, transcribed as nheck, and a whistle.[4]
Distribution
The Gadwall breeds in the northern areas of Europe and Asia, and central North America. In North America, its breeding range lies along the Saint Lawrence River, through the Great Lakes, Alberta, Saskatchewan, the Dakotas, south to Kansas, west to California, and along coastal Pacific Canada and southern coastal Alaska.[3][5] The range of this bird appears to be expanding into eastern North America. This dabbling duck is strongly migratory, and winters farther south than its breeding range, from coastal Alaska, south into Central America, and east into Idaho, Kansas, Ohio, Virginia, and then south all the way into Central America.[3][5] Its conservation status is Least Concern.[1]
In Great Britain, the Gadwall is a scarce-breeding bird and winter visitor, though its population has increased in recent years. It is likely that its expansion was partly through introduction, mainly to England, and partly colonization Great Britain, with continental birds staying to breed in Scotland. It has been reported in the River Avon (Hampshire).
Behaviour
Pair up-ending in KolkataThe Gadwall is a bird of open wetlands, such as prairie or steppe lakes, wet grassland or marshes with dense fringing vegetation, and usually feeds by dabbling for plant food with head submerged. It nests on the ground, often some distance from water. It is not as gregarious as some dabbling ducks outside the breeding season and tends to form only small flocks. This is a fairly quiet species; the male has a hoarse whistling call, and the female has a Mallard-like quack. The young birds are fed insects at first; adults also eat some molluscs and insects during the nesting season. The Gadwall is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
Taxonomy
The Gadwall’s closest relative within the genus Anas is the Falcated Duck, followed by the wigeons.[6]
There are two sub-species although one is extinct:
A. strepera strepera, Common Gadwall the nominate subspecies.[7]
†A. strepera couesi, Coues' Gadwall, extinct circa 1874, was located on Fanning Island.[7]
The etymology of the word Gadwall is not known but the term has been in usage from around 1666.[8]

Eurasian Wigeon

The Wigeon or Eurasian Wigeon (Anas penelope, previously Mareca penelope) is one of three species of wigeon in the dabbling duck genus Anas. It is common and widespread within its range. This species was first described by Linnaeus in his Systema naturae in 1758 under its current scientific name.[2]
Description
This dabbling duck is 42–50 centimetres (17–20 in) long with a 71–80 centimetres (28–31 in) wingspan, and a weight of 1.5 pounds (680 g).[3] The breeding male has grey flanks and back, with a black rear end and a dark green speculum and a brilliant white patch on upper wings, obvious in flight or at rest. It has a pink breast, white belly, and a chestnut head with a creamy crown.[4] In non-breeding (eclipse) plumage, the drake looks more like the female. The female is light brown, with plumage much like a female American Wigeon. It can be distinguished from most other ducks, apart from American Wigeon, on shape. However, that species has a paler head and white axillaries on its underwing. The female can be a rufous morph with a redder head, and a gray morph with a more gray head.[4]
 Distribution
It breeds in the northernmost areas of Europe and Asia.[5] It is the Old World counterpart of North America's American Wigeon. It is strongly migratory and winters further south than its breeding range. It migrates to southern Asia and Africa.[5] In Great Britain and Ireland the Eurasian Wigeon is common as a winter visitor, but scarce as a breeding bird in Scotland, the Lake District, the Pennines and occasionally further south. It can be found as an uncommon winter visitor in the United States on the mid-Atlantic and Pacific coasts. It is a rare visitor to the rest of the United States except for the Four Corners and the southern Appalachians.[3][4]
Behaviour
 and habitatThe Eurasian Wigeon is a bird of open wetlands, such as wet grassland or marshes with some taller vegetation, and usually feeds by dabbling for plant food or grazing, which it does very readily. It nests on the ground, near water and under cover. It is highly gregarious outside of the breeding season and will form large flocks. They will join with flocks of the American Wigeon in the United States, and they also hybridize with them.[3] This is a noisy species. The male has a clear whistle that sounds like: "pjiew pjiew", whereas the female has a low growl : "rawr".
The Eurasian Wigeon is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. Its conservation status is Least Concern.[1]

Northern Shoveler

The Northern Shoveler (Anas clypeata), sometimes known simply as the Shoveler (pronounced /ˈʃʌvələr/), is a common and widespread duck. It breeds in northern areas of Europe and Asia and across most of North America,[2] and is a rare vagrant to Australia. In North America, it breeds along the southern edge of Hudson Bay and west of this body of water, and as far south as the Great Lakes west to Colorado, Nevada, and Oregon.[3][4]
The Northern Shoveler is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.[5] The conservation status of this bird is Least Concern.[1]
Contents [hide]
1 Taxonomy
2 Description
3 Behaviour
4 Habitat and range
5 Footnotes


Taxonomy
This species was described by Linnaeus in his Systema naturae in 1758 under its current scientific name.[6] Usually placed in Anas like most dabbling ducks, it stands well apart from such species as the Mallard and together with the other shovelers and their relatives forms a "blue-winged" group that may warrant separation as genus Spatula.
No living subspecies are accepted today. Fossil bones of a very similar duck have been found in Early Pleistocene deposits at Dursunlu (Turkey). It is unresolved, however, how these birds were related to the Northern Shoveler of today; i.e., whether the differences noted were due to being a related species or paleosubspecies, or attributable to individual variation.[7]
 Description
Northern Shoveler in Brazoria National Wildlife Refuge
Female stretching after bathing in KolkataThis species is unmistakable in the northern hemisphere due to its large spatulate bill. The breeding male has a green head, white breast and chestnut belly and flanks. In flight, pale blue forewing feathers are revealed, separated from the green speculum by a white border. In early fall the male will have a white crescent on each side of the face.[4] In non-breeding (eclipse) plumage, the drake resembles the female.
The female is light brown, with plumage much like a female Mallard, but easily distinguished by the long broad bill, which is gray tinged with orange on cutting edge and lower mandible.[4] The female's forewing is grey.
They are 19 inches long (48 cm) and have a wingspan of 30 inches (76 cm) with a weight of 1.3 pounds (600 g).[3]
Behaviour In flightNorthern Shovelers feed by dabbling for plant food, often by swinging its bill from side to side and using the bill to strain food from the water. It also eats mollusks and insects in the nesting season.
The nest is a shallow depression on the ground, lined with plant material and down, usually close to water.
This is a fairly quiet species. The male has a clunking call, whereas the female has a Mallard-like quack.
 Habitat and range
This is a bird of open wetlands, such as wet grassland or marshes with some emergent vegetation.
This bird winters in southern Europe, Africa, northern South America, and the Malay Archipelago.[2] In North America it winters south of a line from Washington to Idaho and from New Mexico east to Kentucky, also along the Eastern Seaboard as far north as Massachusetts.[3][4] In the British Isles, home to more than 20% of the North Western European population, it is best known as a winter visitor, although it is more frequently seen in southern and eastern England, especially around the Ouse Washes, the Humber and the North Kent Marshes, and in much smaller numbers in Scotland and western parts of England. In winter, breeding birds move south, and are replaced by an influx of continental birds from further north.
This dabbling duck is strongly migratory and winters further south than its breeding range (so far so that there have been four reports in Australia)[citation needed]. It is not as gregarious as some dabbling ducks outside the breeding season and tends to form only small flocks.

Australasian Shoveler

The Australasian Shoveler (Anas rhynchotis) is a species of dabbling duck in the genus Anas. It ranges from 46–53 cm. It lives in heavily vegetated swamps. In Australia it is protected under the National Parks and Wildlife Act, 1974. They occur in southwestern and southeastern Australia, Tasmania, and New Zealand[2].
The male has a blue-grey head with a vertical white crescent in front of the eyes.
The Australasian Shoveler has two subspecies:
A. rhynchotis rhynchotis Australian Shoveler, the nominate race, occurs in southwestern and southeastern Australia and Tasmania[2].
A. rhynchotis variegata New Zealand Shoveler, occurs in New Zealand[2].
The status of the Australasian Shoveler is Least Concern[1].