Terry L. Esker

White-tailed Deer Dispersal Behavior in an Agricultural Environment

ABSTRACT Dispersal behavior was examined for 119 male and 102 female white-tailed deer (Odocoileus virginianus) fawns marked in central and northern Illinois. Fawn movement behavior was recorded for 35 single, 78 pair and 10 triplet litters that survived intact beyond family breakup in late spring. Males (65%) dispersed at a higher rate than females (39%). Females dispersed Apr.–Jul., while males dispersed Apr.–Jul. and Sep.–Nov. The dams and siblings movements most affected fawn movement behavior with most fawns of dispersing/migrating females and siblings leaving their natal range. As yearling-adult densities and forest cover increased on our study areas, female fawn dispersals decreased. Habitat scarcity in spring coupled with high fawn survival into the spring months promoted higher than expected female dispersal behavior. Distance traveled to a new range did not differ among study areas, years or month of dispersal for either sex. Single fawns were as likely to disperse as fawns from pairs or triplets. Control of high density deer populations will be more difficult where female dispersal is prevalent, as in the agriculturally dominated Midwest landscape.

Migration Behavior among Female White-Tailed Deer in Central and Northern Illinois

ABSTRACT Thirty-nine female white-tailed deer (Odocoileus virginianus) were migrators from three study areas in central and northern Illinois, 1980–1993. Migrants averaged 21.5%, 9.4% and 14.6% of marked females known alive each year on the east-central, west-central and northern study areas, respectively. Females migrated to a summer range between late Feb. and early Jul. and to the winter range between late Sep. and early Jan. Spring migration distances averaged between 7.3 and 15.9 km from the winter range. Female fawns of migrating mothers were more likely to disperse or migrate than were fawns of sedentary mothers. Migrating females survived as long as sedentary females and significantly better than females that dispersed, but fawn recruitment was lower for migrating females compared with sedentary females. Winter severity did not affect return behavior from a summer range. Hunter harassment on the summer range initiated migration back to the winter range in 59% of 22 monitored migrations for 14 radio marked females. Prevailing winds from the winter or summer range appeared to help locate these ranges for 10 of 19 spring migrations for 16 females and three of seven fall migrations for four females. Migration behavior allows females to more fully utilize the fragmented landscapes of the agricultural Midwest. Migration behavior among females appears to result from resource competition among females including parturition sites where female densities are high and available habitats are scarce.

Characteristics of Dominant and Subordinate Led Social Groups of White-tailed Deer in Illinois

Abstract This study of dominant and subordinate led social groups of white-tailed deer (Odocoileus virginianus) was designed to investigate longevity and associations among members as well as the reproductive success that determines the durability of these groups. Characteristics of 25 dominant and 17 subordinate female led social groups of white-tailed deer were studied on three areas in Illinois. Group size for dominant led social groups ranged between 3.8 and 5.2 deer/y and for subordinate led groups only 2–2.5 deer. Dominant females survived significantly longer (8.2 y) then did subordinate females (5.4 y) and fawns born to dominants were significantly more sedentary after independence. Fawn recruitment (fawns alive at 1 y) was also significantly higher for fawns born to dominant females. Members of a dominant females social group generally confined themselves to the home range of the dominant female but as they aged were seen less often with her. Dominant females occupied stable habitats free of environmental problems while subordinates occupied ranges with frequent natural and human induced disturbances. By association, fawns of dominant females inherit a stable home range that fosters improved longevity and successful fawn recruitment