Badger (Meles meles) Sett Site Selection in Darwin Reserve, Northwestern Russia

Abstract

Badger (Meles meles) sett site selection was studied in non-optimal habitats of the Darwin Reserve in northwestern Russia. Peat bog areas constitute the greater part of the reserve territory. Because subterranean waters lie close to the surface, soil conditions are unfavorable for sett construction and badgers dig their burrows in old charcoal pits – ring-shaped elevated grounds, which are remains of the charcoal trade of the 19th century. From 1963 to 1998, 599 coal-bunkers were surveyed in the reserve for species using burrows (European Badger Meles meles; Red Fox Vulpes vulpes; and Raccoon Dog Nyctereutes procyonoides). Badgers used only 14% of the charcoal pits for sett construction; 38 of them were mapped in 20012006. They were divided in three groups: 1) charcoal pits with main setts, 2) charcoal pits with outliers, and 3) charcoal pits not used by badgers. For each charcoal pit, we recorded a number of variables related to food and shelter for badgers: size and height of coal pits, abundance of undergrowth on coal pits, areas of different forest types, and length of ecotones in the vicinity of coal pits. Biotope composition of charcoal pit surroundings was similar for all groups of charcoal pits. Badgers preferred mosaics of habitats, as suggested by the extent of forest-swamp borders near setts where badgers find their main food, i.e., frogs. The size and height of the charcoal pits was also important. Big charcoal pits can hold large shelters with a few tunnel systems used by animals to move among chambers and possibly escape accumulation of ectoparasites. Badgers also use large charcoal pits to overwinter.