Diet of Finnish Snowy Owls Nyctea scandiaca

Abstract

The Snowy Owl has, during the last 70 years, bred in Finnish Lapland only in 1974, 1987, and 1988. We collected diet material directly from nest bowls, and from pellets found around the nests and at the resting sites of adults and young. These three parts may give different results of the diet. In the identification, bones of legs and pelvis were used. The Norwegian lemming was the main prey, but also Clethrionomys- and Microtus-voles had large parts in the diet. This diet composition has not been observed earlier. The invasions of Snowy Owls to south have sometimes reached areas with good vole populations, but in other cases the owls have successfully preyed upon larger mammals and birds. The Snowy Owl is thus an effective and opportunistic bird of prey, but breeding is possible only if lemmings or voles are available in very large numbers in the arctic breeding area.