Seasonal home range size and philopatry in two northern white-tailed deer populations

From 1994 to 1997, we compared summer and winter space utilisation by two w hite-tailed deer (Odocoileus virginianus) populations wintering in adjacent areas in southeastern Quebec characterised by deep snow cover. One populat ion lived at low density (10 deer/km(2)) with access to abundant forage in winter (127 000 twigs/ha), whereas for the other, high-density population ( 20 deer/km(2)), forage availability was reduced (68 000 twigs/ha). Because of intraspecific competition for resources, we predicted that deer in the h igh-density population would have smaller home ranges, would exhibit greate r philopatry, and would be more likely to disperse. Deer from both populati ons occupied summer home ranges that were similar in size (1182 ha for adul t males; 1102 ha for adult females; 6033 ha for yearling males; 2528 ha for yearling females) but much larger than home ranges observed elsewhere in N orth America. The high-density population showed a higher level of philopat ry than the low-density population during winter but not during summer. Mos t deer remained migratory during the study (n = 93) but 4 of the 5 that dis persed were from the high-density population. We speculate on the ability o f white-tailed deer populations facing severe winters to adapt to using lar ge home ranges in summer. Our results shed light on how wintering areas app ear and expand.