Abstracts

Abstract: Kiawah Island, SC is an 8,000-acre barrier island with moderate levels of residential/resort development. In 1997-1998, spotlight surveys revealed the island had a high-density (~100 deer/mile2) white-tailed deer (Odocoileus virginianus) herd. We divided the island into 2 areas (treated and control) with similar levels of housing development and deer numbers, and during 1999-2002 remotely delivered prostaglandin to all does seen in the treated area. Pregnancy rates were about 50% lower for does in the treated vs. control area during all 4 years. Spotlight surveys showed lower fawn:doe ratios in the treated vs. control area in 1999 and 2000, but not during 2001. During 2002-2004, we captured and radio-collared newborn fawns to evaluate postnatal fawn mortality in both areas. During the final year of fertility control treatments (2002), there was no significant difference in fawn mortality between areas. However, for 2 years after fertility control treatments ceased, fawn mortality in the treated area decreased (2002–92%; 2003–65%; 2004–77%), while fawn mortality in the control area remained high (2002–87%; 2003–84%; 2004–95%). Bobcat (Lynx rufus) predation accounted for 69% of all mortalities. Coincidentally, 2 adult male bobcats that inhabited the treated area were killed by vehicles prior to the 2003 fawning season. The impact these individual bobcats had on fawn mortality in 2002 is relatively unknown, but during 2004 a single radio-collared adult male bobcat killed 38% of 21 radio-collared fawns in the control area. It is possible that the loss of these bobcats may have contributed to the decrease in fawn mortality in the treated area during 2003 and 2004. Spotlight surveys conducted in 2004 indicate a lower deer density (~40 deer/mile²) on the island.