The Swan goose (Anser cygnoides) is a large goose with a natural breeding range in inland Mongolia, northernmost China, and the Russian Far East. While uncommon in the wild, this species has been domesticated. Introduced and feral populations of its domestic breeds occur in many places outside its natural range. The wild form is also kept in collections, and escapes are not unusual amongst feral flocks of other Anser and Branta geese.
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CrepuscularCrepuscular animals are those that are active primarily during twilight (that is, the periods of dawn and dusk). This is distinguished from diurnal...
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HerbivoreA herbivore is an animal anatomically and physiologically adapted to eating plant material, for example, foliage, for the main component of its die...
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GraminivoreIn zoology, a graminivore (not to be confused with a granivore) is an herbivorous animal that feeds primarily on grass. Graminivory is a form of g...
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FolivoreIn zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less ...
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GranivoreSeed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of pla...
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WaterfowlWaterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans. They ...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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GrazingGrazing is a method of feeding in which a herbivore feeds on plants such as grasses, or other multicellular organisms such as algae. In agriculture...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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GlidingGliding flight is heavier-than-air flight without the use of thrust and is employed by gliding animals. Birds in particular use gliding flight to m...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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Serial monogamySerial monogamy is a mating system in which a pair bonds only for one breeding season.
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FlockingFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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ColonialColonial animals live in large aggregations composed of two or more conspecific individuals in close association with or connected to, one another....
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Dominance hierarchyA dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social gr...
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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DomesticatedDomesticated animals are those adapted to live with humans. It is the mutual relationship between animals and humans who have an influence on their...
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starts withSwan geese are large and long-necked water birds. They are greyish-brown in color, with thin light fringes to the larger feathers and a maroon hindneck and cap (reaching just below the eye). Apart from darker streaks on the belly and flanks, their underside is pale buff. Uniquely among its genus, the long, heavy bill is completely black in color and a thin white stripe surrounds the bill base; the legs and feet, on the other hand, are orange as in most of its relatives. The eyes' irides are maroon. Juveniles are duller than adult birds and lack the white bill base and dark streaks on the underside.
Swan geese breed in Mongolia, northernmost China, and southeastern Russia. They are migratory and winter mainly in central and eastern China. Vagrant birds are encountered in Japan and Korea (where they used to winter), and more rarely in Kazakhstan, Laos, coastal Siberia, Taiwan, Thailand, and Uzbekistan. These birds inhabit taiga, grasslands, steppes and mountain valleys near freshwater lakes and fast-flowing rivers. In winter, they can be found in marshes, estuaries, plains, and rice-fields.
Swan geese are social birds and form small flocks outside the breeding season. They are crepuscular and forage in the morning and evening. These birds rarely swim and most of their time is spent grazing on plants. Swan geese migrate twice a year; spring migration occurs in late February-early April and the autumn migration starts in August and lasts until mid-September. Prior to autumn migration, the birds usually gather in small groups to molt their worn plumage. The voice of Swan geese is a loud drawn-out and ascending honking "aang". They also produce a similar but more barking honk two or three times in short succession as a warning call.
Swan geese are herbivores (graminivores, folivores). They feed mainly on grasses, leaves, roots, sedges and water plants. They will also consume seeds and berries.
Swan geese are serially monogamous and form pair-bonds that last only within one breeding season. They return from the winter grounds around April, and the breeding season starts soon thereafter. Swan geese breed as single pairs or loose groups near marshes and other wetlands and start nesting in May. The clutch is usually 5-8 eggs, which are laid in a shallow nest made from plants, placed directly on the ground, often on a small knoll to keep it dry. Incubation lasts about 28 days done only by a female while the male guards her and the nest. Goslings are precocial; they hatch fully-developed and with eyes open. They fledge 10-11 weeks after hatching and become reproductively mature at 2 to 3 years of age.
Populations of Swan geese are declining due to habitat loss, excessive hunting and (particularly on the Sanjiang Plain in China) egg collecting. In Mongolia, these birds suffer from fires, droughts, and overgrazing.
According to the IUCN Red List, the total Swan goose population size is around 60,000-90,000 individuals. Specific population numbers have been estimated in such areas: in Korea - around 50-1,000 individuals on migration and around 50-1,000 wintering individuals; in Yangtze River wetlands - 87,544 individuals. Overall, currently, Swan geese are classified as Vulnerable (VU) on the IUCN Red List and their numbers today are decreasing.
Due to their grazing habits, Swan geese play an important role in their ecosystem; they provide soil aeration and new habitat for plants which helps new seeds to grow better.
While uncommon in the wild, the Swan goose has been domesticated and introduced and feral populations of its domestic breeds occur in many places outside its natural range. There are two breeds that are direct descendants of the Swan goose: the Chinese goose and the African goose. These breeds have been domesticated since at least the mid-18th century – perhaps even (in China) since around 1000 BC. They vary considerably from their wild parent in appearance, temperament, and ability to produce meat and eggs; the most conspicuous feature is the prominent bill knob and upright posture.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...