Use of multiple den sites by Eurasian badgers, Meles meles, in a Mediterranean habitat

Den sites are a conspicuous feature of Eurasian badgers, Meles meles, and in many environments include large communal burrows used by several group members. In Serra de Grândola, southwest Portugal, nine badgers from three social groups were captured and radio collared from 2000 to 2004. A total of 1,787 locations of badgers in their resting sites were registered along with a brief description of the type of site and weather conditions. Resting sites were grouped according to structure (burrows, shrubs, rocks, hollow trees and man-made structures) and function (main, secondary and occasional). Although main setts were the most frequently used shelter (62.25%), an average of 14 (SD 7.55) resting sites were used in each territory. The pattern of use varied seasonally, showing differences according to sex and social group. Overall, females used more than twice as many occasional resting sites as did males. Generally burrows, predominantly main setts, were most frequently used during winter and autumn, whilst non-burrow shelters were preferred during spring and summer, when the weather was hot, dry and not windy. Proximity to food patches had no apparent influence on the location of resting sites. Our results offered no support for the foraging-related hypotheses that multiple resting sites are a means of conserving energy or of maintaining proximity to rich food patches. We suggest that other factors such as thermoregulation needs, disturbance, and reproductive status, could be influencing the observed pattern of resting-site use by badgers in Serra de Grândola.