Waterfowl (Anatidae) are a large and well-known family of aquatic birds. Among them are geese and swans, which together with whistling ducks we classify in the subfamily of geese (Anserinae), with all other swimming birds grouped in the subfamily of ducks (Anatinae). Waterfowl are adapted to life in the water. Between their toes they have webbing that enables good swimming, and they grease their plumage with oil secreted by special glands at the base of the tail. The oil repels water, so their plumage does not get wet and thus retains its insulating ability.
At Lake Cerknica one can observe during migration or wintering all three species of swans that occur in Slovenia, four species of geese (out of seven that have been observed here), one of the two species of coots, and 19 species of birds from the subfamily Anatinae (ducks); of these, five species also nest at Lake Cerknica. Lake Cerknica is also an important nesting area for the ’Slovenian’ populations of reglje, spoonbills and kostanjevke.
