Many different populations of Greylag Goose occur throughout Europe. The Iceland population breeds in lowland Iceland and migrates each autumn to spend the non-breeding season almost exclusively in Britain and Ireland. Small numbers remain in Iceland and the Faeroes, while others winter in southern Norway.

Co-ordinated censuses of this population began in 1960. From then until 1990, the population increased from around 30,000 to 110,000. Subsequently, it has declined to around 80,000.

Large concentrations occur in early autumn, especially in north and east Scotland, with considerable redistribution later in the winter, particularly further south within Scotland and to northern England and Ireland, although important changes in these patterns have occurred in recent years.