Characteristics, location and selection of diurnal resting dens by Eurasian badgers (Meles meles) in a low density area

Abstract

We describe diurnal resting dens (setts) used by Eurasian badgers Meles meles L. in Coto del Rey, Doñana National Park, south-western Spain, and analyse the factors that determine sett location and selection in relation to territory outlines, soil type and vegetation structure. Setts were located by tracking radio-tagged badgers daily. Badger setts were mainly underground burrow systems with, on average, 2.6 badger entrances. Frequently, badgers constructed setts by enlarging existing rabbit warrens. Setts were located almost everywhere, but badgers preferred easily dug, well-drained soils with good vegetation cover within foraging habitats. A logistic regression model showed that badgers select sites with high surrounding shrub density, large shrubs covering the burrow and close to the centre of the territory (in Mediterranean scrubland habitat). The small size of badger setts in Coto del Rey is common to other low density areas, and probably relates to the extent of use (i.e. age of the burrows and number of badgers using them) of the burrow system. The number of setts per badger territory is related positively to territory size. The similarity of sett densities between this low density population and high density populations, points to a minimum number of setts being required to maximize territory use, and to offer easily-available protection. The preservation and improvement of Mediterranean scrubland vegetation, as well as of large and old shrubs, are important for the future conservation of the badger in Mediterranean landscapes. In these areas, and given the impossibility of distinguishing main setts, the estimation of absolute densities in population surveys using main sett numbers should be avoided in favour of relative indices of abundance.