PINE MARTEN (MARTES MARTES) SELECTION OF RESTING AND DENNING SITES INSCANDINAVIAN MANAGED FORESTS

We examined selection of resting and denning sites by the Eurasian pin e marten (Martes martes) in southern boreal Scandinavia. We radio-inst rumented and monitored 25 pine martens during 1987 and 1989-1991 in tw o managed forest areas at Grimso, Sweden, and Varaldskogen, Norway. Pi ne martens were radio-located at 299 resting sites 358 times, and at 4 9 denning sites 109 times. Cavities in trees and rotten snags were pre ferred by adult females as dens for birthing and early rearing of juve niles. Such cavities were rarely used as resting sites. Use of undergr ound resting sites was negatively correlated with mean 24-hour ambient air temperature (T-a). During winter, marten rested underground at T- a significantly lower than when they rested in trees. Selection of res ting and denning sites may be influenced by predation risks and energe tic constraints. Arboreal cavities for denning and underground sites a s thermal cover appear to be important for Scandinavian pine marten. W e hypothesize that in areas with cold winter temperatures and/or an ab undance of enemies such as the red fox (Vulpes vulpes), the lack of su ch sites may limit pine marten distribution and abundance.