Seasonal migration and home range of roe deer (Capreolus capreolus) in the Italian eastern Alps

Although it has been demonstrated that European roe deer (Capreolus capreolus (L. 1758)) may migrate seasonally in areas with snow gradients, this behaviour remains scarcely understood. From 1999 to 2002, radio-tracking techniques in an Italian alpine area showed that 40% of the 32 monitored roe deer migrated (12.0 +/- 6.2 km, mean +/- SD) from the high-elevation summer ranges to the low-elevation winter ranges. Proportions of migratory deer were similar for fawns and adults and for males and females. We documented a mixed migration strategy, with most deer migrating once to the winter range in years of heavy snowfalls, but many deer migrating inconsistently or only for a short period to the winter range in one year with very scarce snowfalls. Seasonal home-range sizes were similar for migratory and stationary deer, except in a winter with very shallow snow when migrators used unusually large home ranges. In all seasons, migrators showed a lower within home range site fidelity than did stationary deer. Our results indicate that seasonal migrations may be a common strategy exhibited by roe deer living in mountain areas to avoid deep snow, and that variability in climatic conditions might be responsible for the development of variable spatial strategies.