The contrast between summer and winter at northern latitudes is stark. Winter in Iceland is a stormy, cold and dark season. Nearly all Icelandic bird species leave their breeding areas over the winter. The main exceptions are some birds that have established a permanent nesting territory; these pairs generally stay within their territories year-round. A number of birds move from inland regions to coastal areas and shallow marine waters or lakes and rivers.
The majority of birds that breed in Iceland, or 47 species, are migratory birds. Of these species, 25 are considered fully migratory. The remaining 22 species are largely migratory. These birds leave Iceland in late summer or autumn. They spend the winter in other countries or in the open ocean, far from Iceland’s shores. Certain other birds are resident species: 24 non-migratory species, which remain in Iceland over the winter, and 10 largely non-migratory species, which remain for the most part in Iceland during winter.