DIFFERENCES IN TIMING OF PARTURITION, BIRTHING SITES, AND BEDDING SITES OF FAWNS IN SYMPATRIC POPULATIONS OF DEER

Mule deer (Odocoileus hemionus) have been declining throughout the western United States and white-tailed deer (O. virginianus) have remained stable or increased. In areas of sympatry, it is important to understand dynamics between the two species. Crockett County, Texas, provided an area where the two species occurred sympatrically at relatively high densities. In summers 2004-2005, we captured adult deer and fitted them with radiocollars and vaginal-implant transmitters. We monitored vaginal-implant transmitters to record date of parturition, to locate birth sites, and to aid in capture of neonates. We captured 101 neonates (68 mule deer and 33 white-tailed deer). We observed 45 parturition sites and 249 day-time bedding sites of fawns. Parturition in mule deer began ca. 1 month after white-tailed deer. Birth sites of mule deer were at higher elevations and on steeper slopes than those of white-tailed deer. Mule deer gave birth under junipers (Juniperus) more often than did white-tailed deer. Our best model used elevation, height of horizontal hiding cover, type of vegetation, canopy shrub, and an interaction between vegetation type and canopy shrub to differentiate between bedding sites of fawns of mule deer and white-tailed deer. Fawns of mule deer bedded at higher elevations in shorter hiding cover and commonly under junipers, whereas fawns of white-tailed deer commonly bedded under honey mesquite (Prosopis glandulosa) or in herbaceous vegetation. Our data show that fawns partition habitat in a manner similar to adults in this area.