>Cygnus columbianus (Tundra Swan)

Tundra Swan

Tundra Swan (Bewick's Swan/Whistling Swan)
Adult Bewick's Swan, Cygnus columbianus bewickii  Tundra swans (help·info)
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Superorder:	Galloanserae
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anserinae
Tribe:	Cygnini
Genus:	Cygnus
Species:	C. columbianus
Binomial name
Cygnus columbianus (Ord, 1815)
Subspecies
C. c. bewickii (Yarrell, 1830), Bewick's Swan C. c. columbianus (Ord, 1815), Whistling Swan
Synonyms
Anas columbianus Ord, 1815 Cygnus bewickii (Yarrell, 1838) Cygnus bewickii jankowski (lapsus) Cygnus bewickii jankowskii Cygnus columbianus jancowskii (lapsus) Cygnus columbianus jankowskii Olor bewickii (Yarrell, 1838) Olor columbianus (Ord, 1815)

The Tundra Swan (Cygnus columbianus) is a small Holarctic swan. The two taxa within it are usually regarded as conspecific, but are also sometimes split into two species, Cygnus bewickii (Bewick's Swan) of the Palaearctic and the Whistling Swan, C. columbianus proper, of the Nearctic. Birds from eastern Russia (roughly east of the Taimyr Peninsula) are sometimes separated as the subspecies C. c. jankowskii, but this is not widely accepted as distinct, most authors including them in C. c. bewickii. Tundra Swans are sometimes separated in the genus Olor together with the other Arctic swan species.

Bewick's Swan is named after the engraver Thomas Bewick, who specialised in illustrations of birds and animals.

Description

C. columbianus is the smallest of the Holarctic swans, at 115–150 cm (45–59 in) in length, 168–211 cm (66–83 in) in wingspan and a weight range of 3.4–9.6 kg (7.5–21 lb). In adult birds, the plumage of both subspecies is entirely white, with black feet, and a bill that is mostly black, with a thin salmon-pink streak running along the mouthline and – depending on the subspecies – more or less yellow in the proximal part. The iris is dark brown. In birds living in waters that contains large amounts of iron ions (e.g. bog lakes), the head and neck plumage acquires a golden or rusty hue. Pens (females) are slightly smaller than cobs (males), but do not differ in appearance otherwise.

Adult (front) and half-year-old immature Bewick's Swans (C. c. bewickii) wintering in Saitama (Japan)

Immatures of both subspecies are white mixed with some dull grey feathering, mainly on the head and upper neck, which are often entirely light grey; their first-summer plumage is quite white already, and in their second winter they moult into the adult plumage. Their bills are black with a large dirty-pink patch taking up most of the proximal half and often black nostrils, and their feet are dark grey with a pinkish hue. Downy young are silvery grey above and white below.

Bewick's Swans are the smaller subspecies. There is a slight size cline, with the eastern birds being slightly larger; good measurement data only exists for the western populations however. These weigh 3.4–7.8 kg (7.5–17 lb), 6.4 kilograms (14 lb) on average in males and 5.7 kilograms (13 lb) in females. They measure 115–140 cm (45–55 in) in overall length; each wing is 46.9–54.8 cm (18.5–21.6 in) long, on average 51.9 centimetres (20.4 in) in males and 50.4 centimetres (19.8 in) in females. The tarsus measures 9.2–11.6 cm (3.6–4.6 in) in length, the bill 8.2–10.2 cm (3.2–4.0 in), averaging 9.1 centimetres (3.6 in). Bewick's Swan is similar in appearance to the parapatric Whooper Swan (C. cygnus), but is smaller, shorter-necked and has a more rounded head shape, with variable bill pattern, but always showing more black than yellow and having a blunt forward edge of the yellow base patch. Whooper Swans have a bill that has more yellow than black and the forward edge of the yellow patch is usually pointed. The bill pattern for every individual Bewick's Swan is unique, and scientists often make detailed drawings of each bill and assign names to the swans to assist with studying these birds. The eastern birds, apart from being larger, tend towards less yellow on the bill, perhaps indicating that gene flow across Beringia, while marginal, never entirely ceased. An apparent case of hybridization between a Bewick's and a vagrant Whistling Swan has been reported from eastern Siberia.

Adult Whistling Swans (C. c. columbianus). Click to magnify for seeing variation in the yellow bill spots.

Adult Whistling Swan in flight. Seen from below, all "Arctic" swans look almost identical.

Whistling Swans weigh 9.5–21 lb (4.3–9.5 kg) – 16 pounds (7.3 kg) on average in males and 14 pounds (6.4 kg) in females –, and measure 47–59 in (120–150 cm) in length. Each wing is 19.7–22.4 in (50–57 cm) long; the tarsus measures 3.7–4.5 in (9.4–11 cm) in length, and the bill is 3.6–4.2 in (9.1–11 cm) long. C. c. columbianus is distinguished from C. c. bewickii by its larger size and the mostly black bill, with just a small and usually hard to see yellow spot of variable size at the base. It is distinguished from the largely allopatricTrumpeter Swan (C. buccinator) of North America by that species' much larger size and particularly long bill, which is black all over except for the pink mouthline, which is stronger than in the Whistling Swan.

Note that color variations with more or less yellow, or pink instead of yellow or black, are not exceptional, especially in Bewick's Swans, which very rarely may even have yellowish feet. The small size and particularly the rather short neck, which make it look like a large white goose, are still distinguishing marks.

Tundra Swans have high-pitched honking calls and sound similar to a black goose (Branta). They are particularly vocal when foraging in flocks on their wintering grounds; any conspecific arriving or leaving will elicit a bout of loud excited calling from its fellows. Contrary to its common name, the ground calls of the Whistling Swan are not a whistle and neither notably different from that of Bewick's Swan. The flight call of the latter is a low and soft ringing bark, bow-wow...; the Whistling Swan gives a markedly high-pitched trisyllabic bark like wow-wow-wow in flight. By contrast, the Whooper and Trumpeter Swans' names accurately describe their calls – a deep hooting and a higher-pitched French horn-like honk, respectively. Flying birds of these species are shorter-necked and have a quicker wingbeat than their relatives, but they are often impossible to tell apart except by their calls.

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  Head of a Bewick's Swan,C. c. bewickii
 
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  Head of a Whooper Swan,C. cygnus
 
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  Whistling Swan, C. c. columbianus
 
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  Trumpeter Swan, C. buccinator

>Cygnus buccinator (Trumpeter Swan)

Trumpeter Swan

Trumpeter Swan
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anserinae
Tribe:	Cygnini
Genus:	Cygnus
Species:	C. buccinator
Binomial name
Cygnus buccinator Richardson, 1832

The Trumpeter Swan (Cygnus buccinator) is the heaviest native North American bird and is (on average) the largest extant waterfowl species on earth. It is the North American counterpart of the European Whooper Swan.

Description

Adults typically measure 138–158 cm (54–62 in) long, weigh 7.7–12.7 kg (17–28 lb), and have a 203 cm (80 in) wingspan. This is the largest extant species of waterfowl. Exceptionally large male Trumpeters can reach a length of 183 cm (72 in), a wingspan of 3.05 m (10.0 ft) and a weight of 17.2 kilograms (38 lb). The Trumpeter Swan is closely related to the Whooper Swan of Eurasia, and even has been considered the same species by some authorities.

Juvenile at the Cincinnati Zoo

The cygnets (juveniles) are grey in appearance, becoming white after the first year. The Mute Swan can easily be distinguished by its orange bill and different structure (particularly the neck, which is almost always curved down). The Tundra Swan more closely resembles the Trumpeter, but is quite a bit smaller and usually has yellow lores. However, some Trumpeter Swans have yellow lores; many of these individuals appear to be leucistic and have paler legs than typical Trumpeters.Distinguishing Tundra and Trumpeter Swans from a distance (when size is harder to gauge) is quite challenging, and can often be done only with experience and knowledge of structural details.

Range and habitat

In winter, they may eat crop remnants in agricultural fields, but more commonly they feed while swimming

Their breeding habitat is large shallow ponds and wide slow rivers in northwestern and central North America, with the largest numbers of breeding pairs found in Alaska. Natural populations of these swans migrate to and from the Pacific coast and portions of the United States, flying in V-shaped flocks. Released populations are mostly non-migratory. In the winter they migrate to the southern tier of Canada, the eastern part of the northwest states in the United States, especially to the Red Rock Lakes area of Montana, the north Puget Sound region of northwest Washington state; they have even been observed as far south as Pagosa Springs, Colorado. Historically they range as far south as Texas and southern California.

These birds feed while swimming, sometimes up-ending or dabbling to reach submerged food. The diet is almost entirely aquatic plants. In winter, they may also eat grasses and grains in fields. The young are fed on insects and small crustaceans along with plants at first, changing to a vegetation-based diet over the first few months. Predators of Trumpeter Swan eggs includeCommon Raven (Corvus corax), Common Raccoon (Procyon lotor), Wolverine (Gulo gulo),American Black Bear (Ursus americanus), Brown Bear (Ursus arctos), Coyote (Canis latrans), Gray Wolf (Canis lupus) and Northern River Otter(Lontra canadensis). Most of the same predators will prey on young cygnets, as will Common Snapping Turtle (Chelhydra serpentina),California Gull (Larus californicus), Great Horned Owl (Bubo virginianus) and American Mink (Mustela vison). Larger cygnets and rarely nesting adults are preyed on by Golden Eagle (Aquila chrysaetos), Bobcat (Lynx rufus), Red Fox (Vulpes vulpes) and Coyote. Predation of adults when they are not nesting is rare, although they may possibly be hunted by Golden Eagles.

Breeding

Trumpeter Swan brood

The female lays 3–12 eggs on average in a mound of plant material on a small island, a beaver or muskrat lodge, or a floating platform. The same location may be used for several years. The eggs average 73 millimetres (2.9 in) wide, 113.5 millimetres (4.5 in) long, and weigh about 320 grams (11.3 oz). The incubation period is 32 to 37 days. These birds often mate for life, and both parents will participate in raising the cygnets, but only the female will incubate the eggs. The young are able to swim within two days and usually are capable of feeding themselves after at most two weeks. The fledging stage is reached at 3 to 4 months.

Adults go through a summer moult when they temporarily lose their flight feathers. The females become flightless shortly after the young hatch; the males go through this process about a month later when the females have completed their moult.

Conservation status

Three flying in Missouri, USA

Wintering in British Columbia, Canada

In the 19th and early 20th centuries, the Trumpeter Swan was hunted heavily, both as game and a source of feathers. This species is also unusually sensitive to lead poisoning while young. These birds once bred in North America from northwestern Indiana west to Oregon in the U.S., and in Canada from James Bay to the Yukon, and they migrated as far south as Texas and southern California. The trumpeter was rare or extinct in most of the United States by the early twentieth century.Many thousands survived in the core range in Canada and Alaska, however, where populations have since rebounded.

Early efforts to reintroduce this bird into other parts of its original range, and to introduce it elsewhere, have had only modest success, as suitable habitats have dwindled and the released birds do not undertake migrations. More recently, the population in all three major population regions have shown sustained growth over the past thirty year period. Data from the US Fish and Wildlife Service show 400% growth in that period, with signs of increasing growth rates over time.

One impediment to the growth of the Trumpeter Swan population around the Great Lakes is the presence of a growing non-migratory Mute Swan population who compete for habitat.

The Toronto Zoo started a conservation project in 1982, using eggs collected in the wild. Live birds have also been taken from the wild. Since then more than 180 have been released in Ontario. Despite lead poisoning in the wild from shotgun pellets, the prospects for restoration are considered good.

The Trumpeter Swan is listed as threatened in the state of Minnesota

>>Subgenus Olor >Cygnus cygnus (Whooper Swan)

Whooper Swan

Whooper Swan
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anserinae
Tribe:	Cygnini
Genus:	Cygnus
Species:	C. cygnus
Binomial name
Cygnus cygnus (Linnaeus, 1758)
Summer      Resident      Winter

The Whooper Swan (pronounced hooper), Cygnus cygnus, is a large Northern Hemisphere swan. It is the Eurasian counterpart of the North American Trumpeter Swan. An old name for the Whooper Swan is Elk; it is so called in Francis Willughby and John Ray's Ornithology of 1676.

Description

The Whooper Swan is similar in appearance to the Bewick's Swan. However, it is larger, at a length of 140–165 cm (55–65 in) and a wingspan of 205–275 centimetres (81–108 in). Weight typically is in the range of 7.4–14 kilograms (16–31 lb), with an average of 9.8–11 kg (22–24 lb) for males and 8.2–9.2 kg (18–20 lb) for females. The verified record mass was 15.5 kg (34 lb) for a wintering male from Denmark. It is considered to amongst the heaviest flying birds.It has a more angular head shape and a more variable bill pattern that always shows more yellow than black (Bewick's Swans have more black than yellow).

Three Whooper Swans and one Mute Swan

Distribution and behaviour

Whooper swans require large areas of water to live in, especially when they are still growing, because their body weight cannot be supported by their legs for extended periods of time. The whooper swan spends much of its time swimming, straining the water for food, or eating plants that grow on the bottom.

Whooper swans have a deep honking call and, despite their size, are powerful fliers. Whooper swans can migrate many hundreds of miles to their wintering sites in northern Europe and eastern Asia. They breed in subarctic Eurasia, further south than Bewicks in the taiga zone. They are rare breeders in northern Scotland, particularly in Orkney, and no more than five pairs have bred there in recent years. This bird is an occasional vagrant to western North America. Icelandic breeders overwinter in the United Kingdom and Ireland, especially in thewildfowl nature reserves of the Royal Society for the Protection of Birds and of the Wildfowl and Wetlands Trust.

Whooper swans pair for life, and their cygnets stay with them all winter; they are sometimes joined by offspring from previous years. Their preferred breeding habitat is wetland, but semi-domesticated birds will build a nest anywhere close to water. Both the male and female help build the nest, and the male will stand guard over the nest while the female incubates. The female will usually lay 4-7 eggs (exceptionally 12). The cygnets hatch after about 36 days and have a grey or brown plumage. The cygnets can fly at an age of 120 to 150 days.

Influence

Whooper Swans are much admired in Europe. The Whooper Swan is the national bird of Finland and is featured on the Finnish 1 euro coin. The Whooper Swan is one of the species to which theAgreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

The global spread of H5N1 reached the UK in April 2006 in the form of a dead Whooper Swan found in Scotland.

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  Whooper Swan at Welney, United Kingdom
 
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  Whooper Swans near Kilfenora, Co. Clare, Ireland
 
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  Young Whooper Swan at Lake Kussharo, Japan
 
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  Whooper Swans resting at Sunayu Onsen at Lake Kussharo, Japan
 
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  Mute Swans with orange bills and Whooper Swans, with yellow bills

>>Subgenus Sthenelides >Cygnus melancoryphus (Black-necked Swan)

Black-necked Swan

Black-necked Swan
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anserinae
Tribe:	Cygnini
Genus:	Cygnus
Species:	C. melancoryphus
Binomial name
Cygnus melancoryphus Molina, 1782
Synonyms
Anas melancoripha (lapsus) Molina, 1782 Sthenelides melancoryphus Sthenelides melanocoryphus (unjustified emendation) Cygnus melancorypha (a common lapsus) Cygnus melanocoryphus (unjustified emendation)

Taken in Hong Kong park.

The Black-necked Swan (Cygnus melancoryphus) is the largest waterfowl native to South America.

Description

Adults average 102 to 124 cm (40 to 49 in) and weigh 3.5-6.7 kg (7.7-14.8 lbs). The wingspan ranges from 135 to 177 cm (53 to 70 in).The body plumage is white with a black neck, head and greyish bill. It has a red knob near the base of the bill and white stripe behind eye. The sexes are similar, with the female slightly smaller. The cygnet has a light grey plumage with black bill and feet. The Black-necked Swan was formerly placed in monotypic genus, Sthenelides.

The smallest member in its genus, it is found in freshwater marshes, lagoon and lake shores in southern South America. The Black-necked Swan breeds in Chilean Southern Zone, Patagonia,Tierra del Fuego and on the Falkland Islands. In the austral winter, this species migrates northwards to 
Paraguay and southern Brazil. The wetlands created by the Great Chilean Earthquake like Carlos Anwandter Nature Sanctuary in Cruces River have become important population centers for the Black-necked Swan.

In 2004 and 2005 thousands of Black-necked Swans in the Carlos Anwandter Nature Sanctuary in Chile died or migrated away following major contamination by Valdivia Pulp Mill located on theCruces River which feeds the wetlands. By August 2005 the birds in the Sanctuary had been "wiped out"; only four birds could be observed from a population formerly estimated at 5,000 birds. Autopsies on dead swans attributed the deaths to high levels of iron and other metals polluting the water.

The Black-necked Swan, like its nearest relatives the Black and Mute Swan is relatively silent. Also, unlike most wildfowl, both parents regularly carry the cygnets on their backs. The female lays four to six eggs in a nest of vegetation mound. The diet consists mainly of vegetation, insects and fish spawn.

Widespread and common throughout its habitat, the Black-necked Swan is evaluated as Least Concern on the IUCN Red List of Threatened Species. It is listed on Appendix II of CITES.

Gallery

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>Cygnus atratus sumnerensis (New Zealand Swan)

New Zealand Swan

 

New Zealand Swan
Conservation status
Fossil
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anserinae
Tribe:	Cygnini
Genus:	Cygnus
Species:	C. atratus
Subspecies:	C. a. sumnerensis
Trinomial name
Cygnus atratus sumnerensis (Forbes, 1890)
Synonyms
Chenopis sumnerensis Cygnus sumnerensis

The New Zealand Swan (Cygnus atratus sumnerensis) is an extinct swan from the Chatham Islands and the South Island of New Zealand. It was originally described as a separate species from the Black Swan based on the slightly larger size of the fossil bones found and the apparent absence of the Black Swan from New Zealand prior to 1864. More recent analysis of these fossils, and others, suggests that the New Zealand Swan was a subspecies of the Black Swan, and it is referred to this way in ornithology today. The swan remains found in the Chatham Islands may constitute a separate species, C. chathamicus (Oliver, 1955 - C. chathamensis is an unjustified emendation), but more work is needed to establish this.

The Australian form was introduced to New Zealand and the Chatham Islands in 1864 and 1890, respectively. They have effortlessly filled the ecological niche of their extinct relative(s) and multiplied, today numbering in the tens of thousands.