The greylag goose or graylag goose (Anser anser) is a species of large goose in the waterfowl family Anatidae and the type species of the genus Anser. It has mottled and barred grey and white plumage and an orange beak and pink legs. A large bird, it measures between in length, with an average weight of . Its distribution is widespread, with birds from the north of its range in Europe and Asia migrating southwards to spend the winter in warmer places. It is the ancestor of most breeds of domestic goose, having been domesticated at least as early as 1360 BCE. The genus name is from anser, the Latin for "goose".
Greylag geese travel to their northerly breeding grounds in spring, nesting on moorlands, in marshes, around lakes and on coastal islands. They normally mate for life and nest on the ground among vegetation. A clutch of three to five eggs is laid; the female incubates the eggs and both parents defend and rear the young. The birds stay together as a family group, migrating southwards in autumn as part of a flock, and separating the following year. During the winter they occupy semi-aquatic habitats, estuaries, marshes and flooded fields, feeding on grass and often consuming agricultural crops. Some populations, such as those in southern England and in urban areas across the species' range, are primarily resident and occupy the same area year-round.
Taxonomy
Anser anser, the greylag goose, is a member of the waterfowl family Anatidae. It was first described by the Swedish naturalist Carl Linnaeus in 1758 as Anas anser, but was transferred two years later to the new genus Anser, erected by the French zoologist Mathurin Jacques Brisson, where it is the type species. Two subspecies are recognised; A. a. anser, the western greylag goose, which breeds in Iceland and northern and central Europe; A. a. rubrirostris, the eastern greylag goose, which breeds in Romania, Turkey, and Russia eastwards to northeastern China. The two subspecies intergrade where their ranges meet. The greylag goose sometimes hybridises with other species of goose, including the barnacle goose (Branta leucopsis) and the Canada goose (Branta canadensis), and occasionally with the mute swan (Cygnus olor). The greylag goose was one of the first animals to be domesticated; this happened at least 3,000 years ago in Ancient Egypt, the domestic subspecies being known as A. a. domesticus. As the domestic goose is a subspecies of the greylag goose they are able to interbreed, with the offspring sharing characteristics of both wild and domestic birds.
Description
The greylag is the largest and bulkiest of the grey geese of the genus Anser, but is more lightly built and agile than its domestic relative. It has a rotund, bulky body, a thick and long neck, and a large head and bill. It has pink legs and feet, and an orange or pink bill with a white or brown nail (hard horny material at tip of upper mandible). It is long with a wing length of . It has a tail , a bill of long, and a tarsus of . It weighs , with a mean weight of around . The wingspan is . Males are generally larger than females, with the sexual dimorphism more pronounced in the eastern subspecies rubirostris, which is larger than the nominate subspecies on average.
The plumage of the greylag goose is greyish brown, with a darker head and paler breast and belly with a variable amount of black spotting. It has a pale grey forewing and rump which are noticeable when the bird is in flight or stretches its wings on the ground. It has a white line bordering its upper flanks, and its wing coverts are light coloured, contrasting with its darker flight feathers. Its plumage is patterned by the pale fringes of the feathers. Juveniles differ mostly in their lack of black speckling on the breast and belly and by their greyish legs. Adults have a distinctive 'concertina' pattern of folds in the feathers on their necks.
The greylag goose has a loud cackling call similar to that of the domestic goose, "aahng-ung-ung", uttered on the ground or in flight. There are various subtle variations used under different circumstances, and individual geese seem to be able to identify other known geese by their voices. The sound made by a flock of geese resembles the baying of hounds. Goslings chirp or whistle lightly, and adults hiss if threatened or angered.