Shifter and resident red deer: intrapopulation and intersexual behavioural diversities in a predator-free area

Context. Population management of meso-large game species; knowledge of seasonal movements and sexual segregation. Aims.Wepredicted(1)asimilarmixedspatialtacticinthetwosexes(shiftersandresidents);(2)thatreproductivesuccess could be a key factor eliciting a mixed spatial tactic in hinds; and (3) that hunting activities may affect the rutting season, influencing rutting site location. Methods. We studied the spatial behaviour of 41 red deer on the Italian north-eastern Alps, from December 2003 to October 2007, by VHF radio-tracking. Key results. For both sexes, two main spatial tactics were described, including residents, remaining in the same area all year long, and shifters, using non-overlapping seasonal home ranges. Most deer showed consistent spatial behaviour. In all,87%ofstagsand49%ofhindswereshifters.Sexualsegregationwasgreaterinwinterthaninsummer.Allhindswintered in the same valley, with residents in the qualitatively poorer, but protected, area. Resident hinds showed a variable yearly reproductive success, whereas usually all shifters had a calf at heel. Rutting areas of hinds overlapped with their winter or summerranges,whereasstagsoccupieduptothreedifferentareasyearly.Deerdistributiondeterminedadifferentharvesting pressure on the two sexes. Conclusions.Althoughshiftersandresidentswerefoundinbothsexes,differencesinspatialbehaviourofstagsandhinds were consistent for seasonal occupancy, habitat selection and number of seasonal home ranges. For hinds, a mixed spatial tactic, seasonality and hunting activities could be key factors of reproductive success. Implications.Huntingcouldaffecttheproportionsofshifterandresidenthindsatdifferentlevels,withthelatterbenefiting from the protection accorded. This unequally distributed selective harvesting may alter the local social structure and population dynamics in the long term. Shifter behaviour, seasonal movements and sexual segregation may bias population estimates,ifcountsareconductedwhenindividualsmakeseasonalmovements.Furthermore,thesizeofahuntingunitshould be function of the extent of local movements of deer.