The islands are home to only a few species of mammals, including some that were transplanted.
Fallow deer, red deer, roe deer and mountain hare were avidly transplanted during the first decades of the 20th century. Of these, only the fallow deer and hare have survived. Today the fallow deer strain consists of more than 20 animals. Bats and water voles occur naturally. Fox have been spotted on the islands in some years. There also is an abundance of tailless amphibians and reptiles.
Abundant bird life
Bird life on the islands is remarkably profuse. Typical species are ospreys, black-throated loons, several kinds of ducks, crows and ravens as well as mew gulls, herring gulls and terns. Gulls, in particular, put their stamp on the archipelago and nest in several colonies. Other species represented include the greylag goose and marine species such as the greater black-backed gull and Eurasian oystercatcher. The osprey can be considered a characteristic bird in the archipelago. At least three and as many as five pair nest in the area. The web-footed birds present include mallards, widgeons, teals, common goldeneyes, goosanders, red-breasted mergansers and black-throated loons, and among wading birds Eurasian oystercatchers, smaller and larger ringed plovers, common sandpipers, redshanks, common snipes and woodcocks have been noted.