Swans are large water birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae.
Swans usually mate for life, though "divorce" does sometimes occur, particularly following nesting failure. The number of eggs in each clutch is between 3–8.
The word is derived from Old English swan, akin to the German Schwan and Dutch zwaan, in turn derived from Indo-European root *swen (to sound, to sing), whence Latin derives sonus (sound). (Webster's New World Dictionary) Young swans are known as cygnets, from the Latin word for swan, cygnus. An adult male is a cob, from Middle English cobbe (leader of a group); an adult female is a pen (origin unknown).
The Northern Hemisphere species of swan have pure white plumage but the Southern Hemisphere species are white-and-black. The Australian Black Swan (Cygnus atratus) is completely black except for the white flight feathers on its wings, and the South American Black-necked Swan has a black neck.
The legs of swans are dark blackish grey, except for the two South American species, which have pink legs. Bill color varies; the four sub arctic species have black bills with varying amounts of yellow, and all the others are patterned red and black. The Mute Swan and Black-necked Swan have a lump at the base of the bill on the upper mandible.
The Mute Swan (Cygnus olor) is a common Eurasian member of the duck, goose and swan family Anatidae.
This species of bird is found naturally mainly in temperate areas of Europe across western Asia, as far east as the Russian maritimes, near Sidemi (Dement'ev,G.P.(1967), Gmelin(1789) and John Latham(1824) reported Mute Swans present in Kamchatka in the 1700s and still nesting there in 2007. Recorded Mute Swans arriving in Alaska across the Bering Strait.
It is migratory throughout northern latitudes in Europe and Asia, as far south as north Africa. and in the Mediterranean. It is known and recorded to have nested in Iceland and is a vagrant to that area, as well as to Bermuda according to the U.N. Environmental Program chart of international status chart of bird species.
In America, it migrates in the Saskatchewan area, across the Hudson's Bay over the Great Lakes into the States, dispersing there through mid continent. A specimen of Mute Swan dated 1650-1700,was designated as that species by Rufus Churcher, professor of archeology, emeritus, at University of Toronto; Howard Savage, MD, professor and curator of Archaeozoological Comparative Collection at Trent University; Donald Baldwin of Royal Ontario Museum and it appears in Birds from the Ground, a 2003 publication from Trent University, Ontario. Interior swans must often migrate to mid Atlantic coastal locations when lakes freeze over, returning to their nesting area when the lakes open.
The Black Swan, Cygnus atratus is a large water bird which breeds mainly in the southeast and southwest regions of Australia. The Black Swan was formerly placed into a monotypic genus, Chenopis.
‘Swan’ is the common gender 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.
Black Swans are mostly black feathered, with a line of white flight feathers of the wing edges that sometimes show when at rest, and are conspicuous in flight. The bill is bright red, with a pale bar and tip; and legs and feet are grayish-black. Cobs (males) are slightly larger than pens (females), with a longer and straighter bill. Cygnets (immature birds) are a grayish-brown with pale-edged feathers.
A mature Black Swan measures between 1.1 and 1.4 meters in length and weighs up to 9 kg. Its wing span, in flight, is between 1.6 and 2 meters. 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 species has a large range, with figures between one to ten million km² given as the extent of occurrence. The current global population of the Black Swan is estimated to be up to 500,000 individuals. No threat of extinction, or significant decline in population has been identified in 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 compasses 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.
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 Necked Swan
The Black-necked Swan, Cygnus melancoryphus is a large water bird of South America. Adults average 4.7 kg (10.4 lbs), 114 cm (45 in) long and have a wingspan of about 177 cm (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. Both sexes are similar, with a slightly smaller female. 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 the southern South America. The Black-necked Swan breeds in Patagonia, Tierra del Fuego and on the Falkland Islands. In winter, this species migrates northwards to Paraguay and southern Brazil. The Laguna Blanca National Park in Argentina is a protected home of this swan. 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 a pulp mill located on the Mataquito River which feeds the wetlands. By August 2005 the birds in the Sanctuary had been "wiped out"; only 4 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.
The Whooper Swan (Cygnus cygnus) is a large Northern Hemisphere swan. It is the Old World counterpart of the North American Trumpeter Swan.
The Whooper Swan is similar in appearance to the Bewick's Swan. However, it is larger, at a length of 140-160 cm (55-63 in), a wingspan of 205-235 cm (81-93 in) and a weight range of 8-15 kg (17.6-33 lbs). 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).
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 sub arctic Eurasia, further south than Bewick's 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 over winter in England and Ireland, especially in the wildfowl 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.
The Trumpeter Swan, Cygnus buccinator is the largest native North American bird, if measured in terms of weight and length, and is (on average) the largest waterfowl species on earth. Males typically measure from 145–163 cm (57–64 inches) and weigh 11.8 kg (26 lb); females typically range from 139–150 cm (55–60 inches) and weigh 10 kg (22 lb). It is rivaled in size among waterfowl only by the introduced Mute Swan, which is native to Eurasia, but the Trumpeter usually is longer-bodied. Exceptionally large male Trumpeters can reach a length of 183 cm (72 inches), a wingspan of 3 meters (almost 10 ft) and a weight of 17.4 kg (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.
These birds have white plumage with a long neck, a black bill subtly marked with salmon-pink along the mouth line, and short black legs. 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. 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. Adults go through a summer molt 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 molt.
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.
The female lays 3 to 9 eggs 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 mm (2.9 inches) wide, 113.5 mm (4.5 inches) 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 incubation and brooding. 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.
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 include Common 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 Snapping Turtle (Chelhydra serpentina), California Gull (Larus californicus), Great Horned Owl (Bubo virginianus) and American Mink (Mustela vison). Larger cygnets and nesting adults are preyed on by Golden Eagle (Aquila chrysaetos), Bobcat (Lynx rufus), Red Fox (Vulpes vulpes) and Coyote. Few predators, apart from the Bobcat and possibly the Golden Eagle, are capable of taking adults when they are not nesting.
This bird was named for its trumpet-like honk which some compare to the sound of a French horn. The E.B. White novel, The Trumpet of the Swan, is about a Trumpeter Swan which learns to play the trumpet in order to compensate for having been born mute, a reference to another swan, the Mute Swan.
In the 1800s and early 1900s, 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, but their comparatively small numbers in the southern part of their range were reduced to near zero by the mid-twentieth century. Many thousands survived in the core range in Canada and Alaska, however, where populations have since rebounded. 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.
The Tundra Swan (Cygnus columbianus) is a small Holarctic swan. This taxon is sometimes split into two species, Cygnus bewickii (Bewick's Swan) of the Palaearctic and the Whistling Swan C. columbianus of the Nearctic but the present evidence suggests they should be considered subspecies within C. columbianus. Bewick's Swan is named after the engraver Thomas Bewick, who specialised in illustrations of birds and animals.
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.
Bewick's is the smallest of the Holarctic swans, at 115-146 cm (45-58 in) in length, a 170-195 cm (67-77 in) wingspan and a weight range of 4-9.5 kg (8.8-21 lbs). C. c. bewickii is similar in appearance to the Whooper Swan, but is smaller, shorter-necked and has a more rounded head shape, with variable bill pattern, but always showing more black than yellow (the other way around as with Whooper Swans) and tending towards a blunt forward edge of the yellow (Whooper tends towards a more pointed edge). The bill pattern for every bird is unique, and scientists can make detailed drawings of each and give them names to assist with studying this species.
The Whistling Swan is distinguished from C. c. bewickii by its largely black bill with a small yellow spot of variable size at the base. C. c. columbianus also averages one-third bigger than C. c. bewickii. It is distinguished from the Trumpeter Swan of North America by that species' larger size and large bill, which is lined with salmon-pink along the mouth line instead of the yellow dot on the lores.
Females are slightly smaller than males. The immature birds have some dull grey feathering, mainly on the head, and bills with a large dirty pink patch. Their feet are also lighter. In birds living in water that contains large amounts of iron ions like bog lakes, the head and neck plumage acquires a golden hue. They have a high-pitched honking call similar to a Canada Goose. 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 soft ringing bark like bow-wow..., the Whistling Swan gives a markedly high-pitched trisyllabic bark like wow-wow-wow in flight.
Note that color variations with more or less yellow or pink instead of yellow or black are not exceptional, especially in the Palearctic birds.
Systematics and evolution
All evidence suggests that the genus Cygnus evolved in Europe or western Eurasia during the Miocene, spreading all over the Northern Hemisphere until the Pliocene. When the southern species branched off is not known. The Mute Swan apparently is closest to the Southern Hemisphere Cygnus; its habits of carrying the neck curved (not straight) and the wings fluffed (not flush) as well as its bill color and knob indicate that its closest living relative is actually the Black Swan. Given the biogeography and appearance of the subgenus Olor it seems likely that these are of a more recent origin, as evidenced by their modern ranges (which were mostly uninhabitable during the last ice age) and great similarity between the taxa.
- Genus Cygnus
- Subgenus Cygnus
- Mute Swan, Cygnus olor, is a common temperate Eurasian species, often semi-domesticated; descendants of domestic flocks are naturalized in the United States and elsewhere.
- Subgenus Chenopis
- Black Swan, Cygnus atratus of Australia, and introduced in New Zealand.
- New Zealand Swan, Cygnus (atratus) sumnerensis, an extinct subspecies of the Black Swan from New Zealand and the Chatham Islands.
- Subgenus Sthenelides
- Black-necked Swan, Cygnus melancoryphus of South America.
- Subgenus Olor
- Whooper Swan, Cygnus cygnus breeds in Iceland and sub arctic Europe and Asia, migrating to temperate Europe and Asia in winter.
- Trumpeter Swan, Cygnus buccinator is a North American species very similar to the Whooper Swan (and sometimes treated as a subspecies of it), which was hunted almost to extinction but has since recovered
- Whistling Swan, Cygnus columbianus is a small swan which breeds on the North American tundra, further north than other swans. It winters in the USA.
- Bewick's Swan, Cygnus (columbianus) bewickii is the Eurasian form which migrates from Arctic Russia to western Europe and eastern Asia (China, Japan) in winter. It is often considered a subspecies of C. columbianus, creating the species Tundra Swan.
The fossil record of the genus Cygnus is quite impressive, although allocation to the subgenera is often tentative; as indicated above, at least the early forms probably belong to the C. olor - Southern Hemisphere lineage, whereas the Pleistocene taxa from North America would be placed in Olor. A number of prehistoric species have been described, mostly from the Northern Hemisphere. Among them was the giant Siculo-Maltese C. falconeri which was taller (though not heavier) than the contemporary local dwarf elephants (Elephas falconeri).
- Cygnus csakvarensis (Late Miocene of Hungary) - formerly Cygnanser
- Cygnus mariae (Early Pliocene of Wickieup, USA)
- Cygnus verae (Early Pliocene of Sofia, Bulgaria)
- Cygnus liskunae (Middle Pliocene of W Mongolia)
- Cygnus hibbardi (?Early Pleistocene of Idaho, USA)
- Cygnus sp. (Early Pleistocene of Dursunlu, Turkey: Louchart et al. 1998)
- Cygnus equitum (Middle -? Late Pleistocene of Malta and Sicily, Mediterranean)
- Giant Swan, Cygnus falconeri (Middle Pleistocene of Malta and Sicily, Mediterranean)
- Cygnus paloregonus (Middle Pleistocene of WC USA) - includes "Anser" condoni and C. matthewi
- Cygnus sp. (Pleistocene of Australia)
- Cygnus lacustris (Late Pleistocene of Lake Eyre region, Australia) - formerly Archaeocygnus
The supposed fossil swans "Cygnus" bilinicus and "Cygnus" herrenthalsi were, respectively, a stork and some large bird of unknown affinity (due to the bad state of preservation of the referred material).
The Coscoroba Swan (Coscoroba coscoroba) from South America, the only species of its genus, is apparently not a true swan. Its phylogenetic position is not fully resolved; it is in some aspects more similar to geese and shelducks.
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Anseriformes
- Family: Anatidae
- Subfamily: Anserinae
- Genus: Cygnus Bechstein, 1803
Cygnanser Kretzoi, 1957