Habitat and drey sites of the red squirrel Sciurus vulgaris LINNAEUS 1758 in suburban parks of Wroclaw, SW Poland

摘要

Studies were conducted in the late autumn of 2005 and in the early winter of 2005/2006 in 20 suburban parks in the city of Wroclaw, SW Poland. All red squirrel core areas (N=140) were situated in broad-leaved or mixed tree stands. Common oaks were recorded in most squirrel core areas (90.2%). A total of 161 dreys were found. Dreys were located in 18 tree species. The red squirrel builds dreys in most common tree species, which, in addition, provide the largest amount of its staple food (Quercus robur, Tilia cordata, Carpinus betulus and Betula verrucosa; together 71.5%). Broad-leaved species comprised 97.9%, while indigenous species -93.6% of all tree species with dreys. There was a clear preference for locating dreys on treetops, which can be viewed as an anti-predator adaptation. Dreys were located 5 to 25 m above the ground (60.2% of them were 12-18 m above ground), mostly at the very top (28.1%) or 1-3 m below the tops of trees (31.9%). Most dreys (63.1%) were not clustered but 38 (23.8%) formed groups of two, the remaining dreys formed groups of 3-6.