Série com o Cisne-Negro (Cygnus atratus) - Series with the Black Swan - 22-01-2011 - IMG_4951
A Text, in english, from Wikipedia, the free encyclopedia:
Black Swan, photographed in Brasília's Zoo, Brazil.
The Black Swan (Cygnus atratus) is a large waterbird which breeds mainly in the southeast and southwest regions of Australia.
Taxonomy:
Black swans were first seen by Europeans in 1697, when Willem de Vlamingh's expedition explored the Swan River, Western Australia.
The black swan was described scientifically by English naturalist John Latham in 1790. It was formerly placed into a monotypic genus, Chenopis.
The common name ‘Swan’ is a gender neutral term, but ‘cob’ for a male and ‘pen’ for a female are also used, as is ‘cygnet’ for the young. Collective nouns include a ‘bank’ (on the ground) and a ‘wedge’ (in flight). Black Swans can be found singly, or in loose companies numbering into the hundreds or even thousands.
Description:
Black Swans are primarily black feathered birds, with white flight feathers. The bill is bright red, with a pale bar and tip; and legs and feet are greyish-black. Cobs (males) are slightly larger than pens (females), with a longer and straighter bill. Cygnets (immature birds) are a greyish-brown with pale-edged feathers.
A mature Black Swan measures between 110 and 142 cm (43-56 in) in length and weighs 3.7–9 kg (8.1-20 lbs). Its wing span is between 1.6 and 2 metres (5.3-6.5 ft). The neck is long (relatively the longest neck among the swans) and curved in an "S".
The Black Swan utters a musical and far reaching bugle-like sound, called either on the water or in flight, as well as a range of softer crooning notes. It can also whistle, especially when disturbed while breeding and nesting.
The Black Swan is unlike any other Australian bird, although in poor light and at long range it may be confused with a Magpie Goose in flight. However, the black swan can be distinguished by its much longer neck and slower wing beat.
Distribution:
The species has a large range, with figures between one to ten million km² given as the extent of occurrence. The current global population is estimated to be up to 500,000 individuals. No threat of extinction, or significant decline in population has been identified with this numerous and widespread bird.
The Black Swan is common in the wetlands of south western and eastern Australia and adjacent coastal islands. In the south west the range ecompasses an area between North West Cape, Cape Leeuwin and Eucla; while in the east it covers are large region bounded by the Atherton Tableland, the Eyre Peninsula and Tasmania, with the Murray Darling Basin supporting very large populations of black swans. It is uncommon in central and northern Australia.
The Black Swan’s preferred habitat extends across fresh, brackish and salt water lakes, swamps and rivers with underwater and emergent vegetation for food and nesting materials. Permanent wetlands are preferred, including ornamental lakes, but black swans can also be found in flooded pastures and tidal mudflats, and occasionally on the open sea near islands or the shore.
Black Swans were once thought to be sedentary, but the species is now known to be highly nomadic. There is no set migratory pattern, but rather opportunistic responses to either rainfall or drought. In high rainfall years, emigration occurs from the south west and south east into the interior, with a reverse immigration to these heartlands in drier years. When rain does fall in the arid central regions, black swans will migrate to these areas to nest and raise their young. However, should dry conditions return before the young have been raised, the adult birds will abandon the nests and their eggs or cygnets and return to wetter areas.
Black Swans, like many other water fowl, lose all their flight feathers at once when they moult after breeding, and they are unable to fly for about a month. During this time they will usually settle on large, open waters for safety.
Introduced populations
Before the arrival of the Māori in New Zealand, a sub-species of the Black Swan known as the New Zealand Swan had developed in the islands, but was apparently hunted to extinction. In 1864, the Australian Black Swan was introduced to New Zealand as an ornamental waterfowl, and populations are now common on larger coastal or inland lakes, especially Rotorua Lakes, Lake Wairarapa and Lake Ellesmere, and the Chatham Islands.[6] Black Swans have also naturally flown to New Zealand, leading some people to consider them a native rather than exotic species, although the present population appears to be largely descended from deliberate introductions.
The Black Swan is also very popular as an ornamental waterbird in Western Europe, especially Britain, and escapes are commonly reported. As yet the population in Britain is not considered to be self-sustaining and so the species is not afforded admission to the official British List, but the Wildfowl and Wetlands Trust have recorded a maximum of nine breeding pairs in the UK in 2001, with an estimate of 43 feral birds in 2003/04 (though that is undoubtedly an under-estimate given the level of monitoring undertaken).
A colony of Black Swans in Dawlish, Devon has become so well associated with the town that the bird has been the town's emblem for forty years.
Behaviour:
When swimming, black swans hold their necks arched or erect, and often carry their feathers or wings raised in an aggressive display. In flight, a wedge of black swans will form as a line or a V, with the individual birds flying strongly with undulating long necks, making whistling sounds with their wings and baying, bugling or trumpeting calls.
Nesting:
Generally, black swans nest in the wetter winter months (February to September), occasionally in large colonies. A typical clutch contains 4 to 8 greenish-white eggs that are incubated for about 35–40 days. After hatching, the cygnets are tended by the parents for about 6 months until fledging, and may ride on their parent's back for longer trips into deeper water.
A Black Swan nest is essentially a large heap or mound of reeds, grasses and weeds between 1 and 1.5 metres (3-4½ feet) in diameter and up to 1 metre high, in shallow water or on islands. A nest is reused every year, restored or rebuilt as needed. Both parents share the care of the nest. Like other swans, the black swan is largely monogamous, pairing for life (about 6% divorce rate). Recent studies have shown that around a third of all broods exhibit extra-pair paternity.
Sexuality:
An estimated one-quarter of all black swans pairings are homosexual and they steal nests, or form temporary threesomes with females to obtain eggs, driving away the female after she lays the eggs. Several swan species exhibit lifelong homosocial behaviours, and the same phenomenon can also be found in a number of other water-birds, notably geese and flamingos, where it serves as a flexible life strategy.
In swans, the pair is the central social unit. The birds reinforce the unit with frequent preening and sex. When one dies the other will usually live out the remainder of its life alone, which is also the norm for male-female couples. The pair builds nests, raise cygnets and defends the territory. Two cobs, being bigger and stronger than a cob (male) and a pen, (female) can hold down a larger territory, and provide their cygnets with more to eat.
Such same-sex pairs represent a major fitness bonus to a pen, and pens without partners will seek out these couples, have sex with one or other of the cobs and lay eggs in their nest. She is then chased off, not being a part of the pair, and the cobs raise the cygnets themselves. Having access to more food the brood have up to ten times the survival rate of a brood with a heterosexual swan couple. From an evolutionary point of view, this is a very rewarding strategy for the cobs as well.
This situation only holds true as long as a nest and/or a territory is in short supply. The two males will have a fitness loss in that they (1) have no guarantee they are the actual fathers of the cygnets (not being bonded with the female) and (2) will have to split reproduction between them.
A same-sex lifestyle will be advantageous in some situations, but not in others. However, having a partner is a requisite for building a nest and keeping a territory, and an opposite-sex partner may not always be available when forming pairs. Thus, the ability to form a male pair is a normal part of the black swan’s social behaviour and an example of a flexible life strategy in the species.
Conservation:
The Black Swan is protected under the Australian National Parks and Wildlife Act, 1974. It is evaluated as Least Concern on the IUCN Red List of Threatened Species.
Australian culture:
Main article: Black Swan emblems and popular culture
The Black Swan was a literary or artistic image, even before the discovery of Cygnus atratus. Cultural reference has been based on symbolic contrast and as a distinctive motif.
The Black Swan's role in Australian heraldry and culture extends to the first founding of the colonies in the eighteenth century. It has often been equated with antipodean identity, the contrast to the white swan of the northern hemisphere indicating 'Australianess'. The Black Swan is featured on the flag, and is both the state and bird emblem, of Western Australia; it also appears in the Coat of Arms and other iconography of the state's institutions.
Fotografado no Zoológico de Brasília, Brasil.
Um texto, em português, da Wikipédia:
O Cisne-negro (Cygnus atratus) é uma ave aquática australiana . É a ave oficial do estado da Austrália Ocidental.
Pertence à família Anatidae, a que pertencem os patos, gansos, e cisnes.
Podem-se encontrar em todos os estados da Austrália. O animal adulto pode pesar até 9 kg. Ao contrário de muitas outras aves aquáticas, os cisnes negros não têm hábitos migratórios. Passam a sua vida no local onde nasceram.
Nidificam em grandes aterros que constroem, no meio de lagos poucos profundos. Os ninhos são utilizados de ano para ano, reparando-se e reconstruindo-se quando necessário. O ninho está tanto ao cuidado do macho quanto ao cuidado da fêmea. Quando as crias já estão aptas para nadar, com a sua plumagem definitiva, é comum ver famílias inteiras em busca de alimento nos lagos.
Os cisnes são aves aquáticas da sub-família Anserinae, que inclui também os gansos. No seu conjunto formam o género Cygnus, sendo caracterizados pelo longo pescoço e por patas curtas. A sua distribuição geográfica é diversificada, sendo os cisnes do hemisfério norte brancos, enquanto que os do hemisfério sul apresentam plumagem por vezes colorida. Os cisnes formam casais monogâmicos e constroem ninhos onde chocam entre 3 a 8 ovos. Se a nidificação falha, é comum os membros do casal procurarem outro parceiro.
Espécies
Cygnus atratus (Latham, 1790) - Cisne-negro
Cygnus melanocorypha (Molina, 1782) - Cisne-de-pescoço-preto
Cygnus olor (Gmelin, 1789) - Cisne-branco
Cygnus buccinator Richardson, 1831 - Cisne-trombeteiro
Cygnus columbianus (Ord, 1815) - Cisne-pequeno
Cygnus bewickii Yarrel, 1830 - Cisne-de-bewick
Cygnus cygnus (Linnaeus, 1758) - Cisne-bravo
Cisnes na Cultura:
O Patinho Feio, um conto de Hans Christian Andersen
O Lago dos Cisnes, um bailado
Cisne Negro Companhia de Dança (Brasil)
Os cisnes aparecem na face nacional das Moedas de euro finlandesas
Cygnus é o nome de uma constelação.
Série com o Cisne-Negro (Cygnus atratus) - Series with the Black Swan - 22-01-2011 - IMG_4951
A Text, in english, from Wikipedia, the free encyclopedia:
Black Swan, photographed in Brasília's Zoo, Brazil.
The Black Swan (Cygnus atratus) is a large waterbird which breeds mainly in the southeast and southwest regions of Australia.
Taxonomy:
Black swans were first seen by Europeans in 1697, when Willem de Vlamingh's expedition explored the Swan River, Western Australia.
The black swan was described scientifically by English naturalist John Latham in 1790. It was formerly placed into a monotypic genus, Chenopis.
The common name ‘Swan’ is a gender neutral term, but ‘cob’ for a male and ‘pen’ for a female are also used, as is ‘cygnet’ for the young. Collective nouns include a ‘bank’ (on the ground) and a ‘wedge’ (in flight). Black Swans can be found singly, or in loose companies numbering into the hundreds or even thousands.
Description:
Black Swans are primarily black feathered birds, with white flight feathers. The bill is bright red, with a pale bar and tip; and legs and feet are greyish-black. Cobs (males) are slightly larger than pens (females), with a longer and straighter bill. Cygnets (immature birds) are a greyish-brown with pale-edged feathers.
A mature Black Swan measures between 110 and 142 cm (43-56 in) in length and weighs 3.7–9 kg (8.1-20 lbs). Its wing span is between 1.6 and 2 metres (5.3-6.5 ft). The neck is long (relatively the longest neck among the swans) and curved in an "S".
The Black Swan utters a musical and far reaching bugle-like sound, called either on the water or in flight, as well as a range of softer crooning notes. It can also whistle, especially when disturbed while breeding and nesting.
The Black Swan is unlike any other Australian bird, although in poor light and at long range it may be confused with a Magpie Goose in flight. However, the black swan can be distinguished by its much longer neck and slower wing beat.
Distribution:
The species has a large range, with figures between one to ten million km² given as the extent of occurrence. The current global population is estimated to be up to 500,000 individuals. No threat of extinction, or significant decline in population has been identified with this numerous and widespread bird.
The Black Swan is common in the wetlands of south western and eastern Australia and adjacent coastal islands. In the south west the range ecompasses an area between North West Cape, Cape Leeuwin and Eucla; while in the east it covers are large region bounded by the Atherton Tableland, the Eyre Peninsula and Tasmania, with the Murray Darling Basin supporting very large populations of black swans. It is uncommon in central and northern Australia.
The Black Swan’s preferred habitat extends across fresh, brackish and salt water lakes, swamps and rivers with underwater and emergent vegetation for food and nesting materials. Permanent wetlands are preferred, including ornamental lakes, but black swans can also be found in flooded pastures and tidal mudflats, and occasionally on the open sea near islands or the shore.
Black Swans were once thought to be sedentary, but the species is now known to be highly nomadic. There is no set migratory pattern, but rather opportunistic responses to either rainfall or drought. In high rainfall years, emigration occurs from the south west and south east into the interior, with a reverse immigration to these heartlands in drier years. When rain does fall in the arid central regions, black swans will migrate to these areas to nest and raise their young. However, should dry conditions return before the young have been raised, the adult birds will abandon the nests and their eggs or cygnets and return to wetter areas.
Black Swans, like many other water fowl, lose all their flight feathers at once when they moult after breeding, and they are unable to fly for about a month. During this time they will usually settle on large, open waters for safety.
Introduced populations
Before the arrival of the Māori in New Zealand, a sub-species of the Black Swan known as the New Zealand Swan had developed in the islands, but was apparently hunted to extinction. In 1864, the Australian Black Swan was introduced to New Zealand as an ornamental waterfowl, and populations are now common on larger coastal or inland lakes, especially Rotorua Lakes, Lake Wairarapa and Lake Ellesmere, and the Chatham Islands.[6] Black Swans have also naturally flown to New Zealand, leading some people to consider them a native rather than exotic species, although the present population appears to be largely descended from deliberate introductions.
The Black Swan is also very popular as an ornamental waterbird in Western Europe, especially Britain, and escapes are commonly reported. As yet the population in Britain is not considered to be self-sustaining and so the species is not afforded admission to the official British List, but the Wildfowl and Wetlands Trust have recorded a maximum of nine breeding pairs in the UK in 2001, with an estimate of 43 feral birds in 2003/04 (though that is undoubtedly an under-estimate given the level of monitoring undertaken).
A colony of Black Swans in Dawlish, Devon has become so well associated with the town that the bird has been the town's emblem for forty years.
Behaviour:
When swimming, black swans hold their necks arched or erect, and often carry their feathers or wings raised in an aggressive display. In flight, a wedge of black swans will form as a line or a V, with the individual birds flying strongly with undulating long necks, making whistling sounds with their wings and baying, bugling or trumpeting calls.
Nesting:
Generally, black swans nest in the wetter winter months (February to September), occasionally in large colonies. A typical clutch contains 4 to 8 greenish-white eggs that are incubated for about 35–40 days. After hatching, the cygnets are tended by the parents for about 6 months until fledging, and may ride on their parent's back for longer trips into deeper water.
A Black Swan nest is essentially a large heap or mound of reeds, grasses and weeds between 1 and 1.5 metres (3-4½ feet) in diameter and up to 1 metre high, in shallow water or on islands. A nest is reused every year, restored or rebuilt as needed. Both parents share the care of the nest. Like other swans, the black swan is largely monogamous, pairing for life (about 6% divorce rate). Recent studies have shown that around a third of all broods exhibit extra-pair paternity.
Sexuality:
An estimated one-quarter of all black swans pairings are homosexual and they steal nests, or form temporary threesomes with females to obtain eggs, driving away the female after she lays the eggs. Several swan species exhibit lifelong homosocial behaviours, and the same phenomenon can also be found in a number of other water-birds, notably geese and flamingos, where it serves as a flexible life strategy.
In swans, the pair is the central social unit. The birds reinforce the unit with frequent preening and sex. When one dies the other will usually live out the remainder of its life alone, which is also the norm for male-female couples. The pair builds nests, raise cygnets and defends the territory. Two cobs, being bigger and stronger than a cob (male) and a pen, (female) can hold down a larger territory, and provide their cygnets with more to eat.
Such same-sex pairs represent a major fitness bonus to a pen, and pens without partners will seek out these couples, have sex with one or other of the cobs and lay eggs in their nest. She is then chased off, not being a part of the pair, and the cobs raise the cygnets themselves. Having access to more food the brood have up to ten times the survival rate of a brood with a heterosexual swan couple. From an evolutionary point of view, this is a very rewarding strategy for the cobs as well.
This situation only holds true as long as a nest and/or a territory is in short supply. The two males will have a fitness loss in that they (1) have no guarantee they are the actual fathers of the cygnets (not being bonded with the female) and (2) will have to split reproduction between them.
A same-sex lifestyle will be advantageous in some situations, but not in others. However, having a partner is a requisite for building a nest and keeping a territory, and an opposite-sex partner may not always be available when forming pairs. Thus, the ability to form a male pair is a normal part of the black swan’s social behaviour and an example of a flexible life strategy in the species.
Conservation:
The Black Swan is protected under the Australian National Parks and Wildlife Act, 1974. It is evaluated as Least Concern on the IUCN Red List of Threatened Species.
Australian culture:
Main article: Black Swan emblems and popular culture
The Black Swan was a literary or artistic image, even before the discovery of Cygnus atratus. Cultural reference has been based on symbolic contrast and as a distinctive motif.
The Black Swan's role in Australian heraldry and culture extends to the first founding of the colonies in the eighteenth century. It has often been equated with antipodean identity, the contrast to the white swan of the northern hemisphere indicating 'Australianess'. The Black Swan is featured on the flag, and is both the state and bird emblem, of Western Australia; it also appears in the Coat of Arms and other iconography of the state's institutions.
Fotografado no Zoológico de Brasília, Brasil.
Um texto, em português, da Wikipédia:
O Cisne-negro (Cygnus atratus) é uma ave aquática australiana . É a ave oficial do estado da Austrália Ocidental.
Pertence à família Anatidae, a que pertencem os patos, gansos, e cisnes.
Podem-se encontrar em todos os estados da Austrália. O animal adulto pode pesar até 9 kg. Ao contrário de muitas outras aves aquáticas, os cisnes negros não têm hábitos migratórios. Passam a sua vida no local onde nasceram.
Nidificam em grandes aterros que constroem, no meio de lagos poucos profundos. Os ninhos são utilizados de ano para ano, reparando-se e reconstruindo-se quando necessário. O ninho está tanto ao cuidado do macho quanto ao cuidado da fêmea. Quando as crias já estão aptas para nadar, com a sua plumagem definitiva, é comum ver famílias inteiras em busca de alimento nos lagos.
Os cisnes são aves aquáticas da sub-família Anserinae, que inclui também os gansos. No seu conjunto formam o género Cygnus, sendo caracterizados pelo longo pescoço e por patas curtas. A sua distribuição geográfica é diversificada, sendo os cisnes do hemisfério norte brancos, enquanto que os do hemisfério sul apresentam plumagem por vezes colorida. Os cisnes formam casais monogâmicos e constroem ninhos onde chocam entre 3 a 8 ovos. Se a nidificação falha, é comum os membros do casal procurarem outro parceiro.
Espécies
Cygnus atratus (Latham, 1790) - Cisne-negro
Cygnus melanocorypha (Molina, 1782) - Cisne-de-pescoço-preto
Cygnus olor (Gmelin, 1789) - Cisne-branco
Cygnus buccinator Richardson, 1831 - Cisne-trombeteiro
Cygnus columbianus (Ord, 1815) - Cisne-pequeno
Cygnus bewickii Yarrel, 1830 - Cisne-de-bewick
Cygnus cygnus (Linnaeus, 1758) - Cisne-bravo
Cisnes na Cultura:
O Patinho Feio, um conto de Hans Christian Andersen
O Lago dos Cisnes, um bailado
Cisne Negro Companhia de Dança (Brasil)
Os cisnes aparecem na face nacional das Moedas de euro finlandesas
Cygnus é o nome de uma constelação.