Greylag Goose
Anser anser
The Greylag Goose is the largest and bulkiest of the grey geese, featuring a robust orange or pinkish bill and pink legs. It inhabits wetlands, lakes, and river valleys across much of Eurasia. Known for its social behavior, it often forms large flocks during migration and molting. It is the wild ancestor of most domestic geese in Europe.
Details
Identification
Large grey-brown body, pale forewing in flight, robust orange to pinkish bill, pink legs.
Social behavior
Highly social, lives in lifelong monogamous pairs and large family groups or flocks.
Diet
Purely herbivorous; feeds on grasses, herbs, roots, grains, and various aquatic plants.
Hunting strategy
Grazing on meadows and fields or dabbling in shallow water zones.
Overwintering
Migration to warmer areas or staying at ice-free water bodies with access to grazing areas.
Ecology
Ecological role
Important grazer influencing vegetation structures; serves as prey for large raptors and predatory mammals.
Natural predators
White-tailed Eagle, Red Fox (clutches and goslings), Raccoon, Common Raven (eggs).
Competitor species
Canada Goose, Mute Swan (competition for nesting sites and food resources).
Ecosystem service
Nutrient transport between aquatic and terrestrial habitats via excrement; seed dispersal.
Threats
Habitat loss due to drainage, disturbance at nesting sites, lead poisoning from hunting ammunition, illegal hunting.
Scientific profile
Morphology & ID
Breeding plumage
Grey-brown barred, underparts paler with irregular black spots in adults. In flight, the light grey forewings (wing coverts) are the most prominent diagnostic feature.
Non-breeding plumage
No distinct seasonal change between breeding and non-breeding plumage; the plumage remains largely identical throughout the year.
Juvenile plumage
Similar to adults but lacking black belly spots. Feather fringes are narrower and less contrasting; legs are more greyish-flesh colored rather than pink.
Sexual dimorphism
Minimal; males (ganders) are on average slightly larger and heavier than females, though this is difficult to distinguish in the field.
Distinguishing features
Large, robust bill (orange or pink), light grey forewings in flight, pink legs, thick neck, and bulky body.
Confusion species
Bean Goose (Anser fabalis - darker head, orange-black bill), Greater White-fronted Goose (Anser albifrons - white blaze on forehead, smaller stature), Pink-footed Goose (Anser brachyrhynchus).
Bill
Robust and wedge-shaped. Mostly orange in the western subspecies (A. a. anser), more pinkish in the eastern subspecies (A. a. rubrirostris).
Vocalization
Song
No passerine-like song; communication occurs through a wide repertoire of calls.
Call
A loud, deep, and nasal 'ga-ga-ga', very similar to the domestic goose. Often uttered in flight or when excited.
Distribution & migration
Breeding range
Palearctic; from Iceland through Northern and Central Europe to Central Asia and China.
Wintering range
Western Europe (Netherlands, Spain), Mediterranean, North Africa, and South Asia. Increasingly wintering in Central European breeding grounds.
Migration details
Partial migrant; northern populations migrate southwest, while Central European birds are often residents or short-distance migrants.
Habitat
Breeding habitat
Eutrophic standing waters, lakes, marshes, and oxbows with extensive reed beds and adjacent grazing areas.
Foraging habitat
Grassland, arable fields (cereals, oilseed rape, maize stubble), wet meadows, and in winter also winter crops.
Breeding biology
Nest construction
Large mound of plant material such as reeds and twigs; the nest cup is lined with fine down feathers.
Eggs
Creamy white to yellowish-white, dull, often stained by nesting material during the course of incubation.
Parental care
Both parents lead the young (precocial); the female incubates alone while the male guards the nest.
Diet & behaviour
Diet breeding
Strictly herbivorous: grasses, herbs, roots, and shoots of aquatic plants.
Diet winter
Winter cereals, oilseed rape, maize kernels on stubble fields, sugar beet remains, and grasses.
Feeding technique
Grazing on land, upending (dabbling) in shallow water, digging for roots and tubers.
Foraging strategy
Herbivorous grazer; searches for food on the ground or in the shallow water zone.
Sociality
Highly social; organized in large flocks outside the breeding season. Forms lifelong monogamous pairs.
Flock behaviour
Formation of V-shapes in flight to save energy; coordinated vigilance within the group during foraging.
Protection & threats
Main threats
Habitat loss due to drainage of wetlands, disturbance at breeding sites by recreational activities, illegal hunting.
Population trend
Increasing; strong population growth and range expansion in Central Europe since the 1970s.
Conservation measures
Protection and restoration of wetlands, management of hunting seasons, establishment of disturbance-free resting zones.