Details

Autor(en) / Beteiligte

• Solheim, Roar
• Stjernberg, T
• Haila, Y (eds)

Titel

Caching behaviour, prey choice and surplus killing by Pygmy Owls Glaucidium passerinum during winter, a functional response of a generalist predator

Ist Teil von

• Annales Zoologici Fennici [ANN. ZOOL. FENN.]. Vol. 21, no. 3. 1984, 1984-01, Vol.21 (3), p.301-308

Ort / Verlag

Finnish Academy of Sciences, Societas Scientiarum Fennica, Societas pro Fauna et Flora Fennica and Societas Biologica Fennica Vanamo

Erscheinungsjahr

1984

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Nestboxes with different-sized entrance holes were put out to study caching behaviour and prey choice of Pygmy Owls in southeastern Norway in the winters 1971/72 to 1976/77. Pygmy Owls preferred nestboxes with entrance holes less than 55 mm for caching, while nestboxes with larger holes were primarily used as sheltered feeding sites. Caching took place from October to April, with a peak in November to January. Single caches contained up to 97 prey items, and regular surplus killing by individual Pygmy Owls may explain the sudden filling up of caches. Of the 1321 prey items identified, 1173 were small mammals. The bank vole Clethrionomys glareolus was the most frequent prey species. Birds were taken in the highest proportions in years of low vole abundance. Choice of caching sites is discussed as an adaptation to avoid cache-robbing from other species. Caching may itself be an adaptation to fluctuating prey availability during winter. The flocking of tits during winter is discussed as a possible antipredatory behaviour pattern to reduce the predation risk from Pygmy Owls.