Habitat selection of Eurasian Scops Owl Otus scops on thenorthern border of its range, central Slovenia

摘要

Habitat selection of the Eurasian Scops Owl Otus scops was studied inLjubljansko barje (central Slovenia, 180 km2) where abiotic conditions, espe-cially climate, could be considered suboptimal for this xerothermophilic species.Data on the number and distribution of calling males were gathered in May andJune 2004-06 using the playback method. A total of 137 calling males werecounted (29 in 2004, 66 in 2005, 42 in 2006). To avoid pseudo-replication, 72non-overlapping sites were selected for habitat analysis. Habitat within 250-mradius plots surrounding owl sites was compared with 136 unoccupied and non-overlapping sites. Within plots, 14 habitat variables were measured.Discriminating variables between occupied and non-occupied sites were identi-fied with stepwise logistic regression. Scops Owl occupation was positivelyassociated with the number of tree lines, and slightly negative with the surfacearea of woodland and settlements. Scops Owls preferred sites with a higherthan average proportion of traditional orchards, tree lines, scrub, unimprovedmeadows, and tree plantations. Tree plantations were only used by owls during2005, when the number of calling males was highest. All males were unpaired,perhaps indicating inexperienced or late-arriving males outcompeted to mar-ginal habitat. Conservation actions needed to maintain this population of ScopsOwl at the northern border of its breeding range include: (1) preserve and reju-venate traditional orchards and isolated trees in farmyards, (2) encourage reno-vation of old houses and their farmyards and discourage high density housing,(3) protect and restore tree lines and copses, (4) enlarge the proportion ofunimproved meadows, and (5) limit the increase of cropland and the use of bio-cides.