Parturition Behavior and Territoriality in White-Tailed Deer: Impact on Neonatal Mortality

Mother-infant behavior in a supplementally-fed captive herd of white-tailed deer (Odocoileus virginianus) was investigated to determine if crowding influenced fawn-rearing success. All does studied isolated themselves at parturition and demonstrated territorial characteristics lasting about 4 weeks if their progeny lived. Matriarch does defended the same fawning area annually; primiparous (2-year-old) daughters occupied adjacent exclusive sites, whereas 3-year-olds established new grounds away from the family group. Unsuccessful mothers failed to exhibit any prolonged solitary or aggressive behavior. Triplet siblings shared a common home range after 2 weeks, but bedded separately until 1 month old. Although fawns traveled more as they grew older, their movement distance during the first 2 months did not change. Doe-fawn spacing decreased after 2 weeks postpartum in the case of a singleton, but not until a month later for the triplet litter. A mother and her fawn(s) did not continuously associate with other deer before the 3rd month. Because whitetails forcefully defend a fawning ground, and complete isolation is essential for proper mother-infant bond formation, we conclude that crowding at peak herd density limited fawn rearing space, disrupted maternal behavior, and thus caused excessive neonatal mortality among fawns of 2and 3-year-old does. J. WILDL. MANAGE. 46(1):1-11 Neonatal behavior in white-tailed deer has been intensively investigated (Cook et al. 1967, Jackson et al. 1972, White et al. 1972, Jacobsen 1979), and features of maternal care have been reported for penned animals (Townsend and Bailey 1975, Langenau and Lerg 1976). Relatively little is known about mother-infant relationships at parturition. Moreover, the newborn fawn is a "hider" (Lent 1974), remaining inactive and virtually undetectable until the mother returns to groom and nurse it once or twice daily. Does tend to be hostile toward other deer at parturition, but such interactions are commonly regarded as defense of the fawn rather than being truly territorial in nature (McCullough 1979). In monitoring the reproductive performance of a supplementally-fed captive deer herd, we noted a drastic rise in neonatal mortality as the population increased to a high level (Ozoga and Verme 1982). Most of this loss was fawns of 2-year-old (primiparous) does; indirect evidence indicated that most fawns died shortly after birth (Ozoga et al. 1982). The purpose of the present study was to document mother-infant behavior and spacing during the parturition season in an effort to assess whether extreme crowding and attendant social tension were responsible for low fawn survival under these circumstances. This paper is a contribution from Michigan Federal Aid in Wildlife Restoration Project W-117-R and the Cusino Wildlife Research Station. The senior author wishes to acknowledge the assistance of his wife Janice, son John Jr., and J. H. Fitch in gathering behavioral data. We thank various DNR personnel for aiding in this endeavor, especially D. L. DeLisle and L. J. Perry; C. L. Bennett was instrumental in initiating the study; and E. E. Langenau provided helpful criticism of the manuscript. We are particularly indebted to U. S. Seal for providing certain telemetry equipment.