Greylag Goose

The greylag goose (Anser anser) is a large goose found across much of Eurasia, with introduced populations in Australia and New Zealand. The species is believed to be the ancestors of most domesticated goose breeds. It is recognizable by its bulky shape and large bill. Adult greylag geese typically have a body length ranging from 74 to 84 cm (29 to 33 in), with a wingspan of 147 to 180 cm (4 ft 10 in to 5 ft 11 in), and can weigh between 2.5 to 4.1 kg (5.5-9.0 lbs). They are characterized by their grey feathers, slightly lighter underbelly, pink legs and an orange or pink bill. The greylag goose cam be distinguished from similar geese by its often larger size, uniformly colored bill, its lack of any facial markings, and vocalizations.

Greylag geese are adaptable birds found in a variety of habitats, including marshes, rivers, lakes, and agricultural fields. They are omnivorous but primarily feed on grasses, roots, grains, and occasionally small aquatic animals. They are known for their “grazing” behavior in fields, which distinguishes their feeding habits from some other goose species that might prefer more aquatic diets.

Greylag geese are highly social birds, known for forming strong family bonds and large flocks, especially during migration and wintering. These geese are vocal communicators, using a variety of calls to maintain group cohesion, signal alarm, and communicate within the family unit. Parent geese are notably attentive and protective of their young, leading them to feeding sites and teaching them to forage.

During the breeding season, greylag geese are territorial and may exhibit aggressive behavior to defend their nesting area from intruders, including other geese. Outside of breeding, they are more gregarious and can be seen in mixed-species flocks with other waterfowl.

Their social structure facilitates learning and adaptation, as younger geese learn migration routes and feeding grounds from older, experienced members of the flock. This social learning is crucial for the survival of migratory populations, ensuring that they can navigate to suitable habitats throughout the year.

Greylag geese exhibit variable migration patterns. Populations in the northern parts of their range tend to migrate southwards during the winter, while those in milder climates may remain in the same area year-round. Their migration is dependent on the availability of food and nesting sites, as well as weather conditions.

The breeding season begins in March or April, often with a top in egg-laying in May. Greylag geese are monogamous and typically nest on the ground, often on islands in lakes or in dense vegetation to avoid predators. They lay 4 to 6 eggs per clutch, which are incubated primarily by the female for about 27 to 28 days. Goslings are precocial and can leave the nest within a day of hatching, but they remain with their parents for several months.

The greylag goose has a wide range, and a large population that is believed to be increasing. It does well near human habitation, which helps with the success of the species. It is listed as least concern on the IUCN Red List. Habitat loss and hunting can affect some local populations.