ECOLOGICAL AND BEHAVIORAL CORRELATES OF DEER SOCIALITY: A STUDY OF OSSABAW ISLAND WHITE-TAILED DEER (TIME BUDGETS, GROUP SIZE, FORAGING STRATEGIES

The behavior of white-tailed deer (Odocoileus virginianus) was studied in 3 habitats--forest, wooded pasture, and open pasture--on Ossabaw Island, Georgia. Deer forages in the forest were mostly from the tree canopy and were scarce and patchily distributed; forages in wooded and open pasture were abundant and less spatially variable. Forest and wooded pasture differed from open pasture in cover density. Groups were smaller in forest and wooded pasture than in open pasture thus group size did not track forage characteristics. Deer in forest and wooded pasture spent more time alert than deer in open pasture. This indicates that deer in dense cover are more vulnerable to predation than deer in the open, contrary to previous hypotheses. Larger groups in all habitats enjoyed the advantages of greater feeding time and lowered vigilance. No evidence was found for the limitation of group size in dense cover through competition, either exploitative or aggressive. Group size may have been limited in forest by the inability of individuals to maintain contact with other group members; nearest-neighbor distances varied greatly through time in forest. More adult bucks used the higher quality wooded and open pasture habitats than adult does or fawns. Adult bucks may have aggressively excluded does and fawns from these areas. Fawns were frequently associated with adult does until winter, presumably as an adaptation to reduce predation of the fawns during their most vulnerable period. Few age-sex class differences in time budgets were found. Deer were less likely to flee at greater distances in all habitats (especially in open pasture) and were more likely to flee when in larger groups. The percent of groups flagging was higher in forest than in open pasture. Snorting (an auditory alarm signal) was more common in larger groups but was not more common in doe-fawn groups as previously reported. Snorting may function as a signal to the predator that it has been detected and presumably evolved through individual selection.