Comparison of spotlight counts and trail camera surveys for censusing white-tailed deer populations, and, Effects of density and supplemental feed on white-tailed buck breeding system

Infrared trail camera (ITC) surveys and spotlight counts have been used to estimate white-tailed deer (Odocoileus virginanus) population sizes, however, there has not been a study comparing the 2 methods. I conducted 12-day baited ITC surveys during February 2006 and spotlight counts during October 2006 on 11 closed populations and compared results to base estimates derived from extended un-baited ITC surveys. Four of 6 12-day ITC estimates in enclosures with no supplemental feed using a method based on identifying individual bucks fell within the 95% confidence interval (CI) of base estimates. Two estimates that did not fall within the 95% CI were underestimates which may have been influenced by high deer densities and/or low buck:doe ratios. Buck:doe ratios derived from 12-day ITC censuses were lower than base estimate ratios (P = 0.015), indicating that the doe segment may be under-represented. Six of 11 spotlight counts using fixed width transects fell within the 95% CI base estimates. All 5 estimates that did not fall within the 95% CI were underestimates which may indicate that spotlight counts with fixed width transects often under-represent the actual deer population. Furthermore, more accurate population estimates were obtained from areas that were open and lacked supplemental feed. Both census methods have strengths and weaknesses, but overall, the ITC survey was more accurate. Additional studies are needed on the influence of baiting, sex bias, and length of ITC surveys.; White-tailed deer thrive under many different demographic and environmental conditions and exhibit a great deal of behavioral plasticity in response to those conditions. However, relatively little is known about white-tailed deer behavior, especially mating behaviors. A 2-year study was conducted on 2 ranches in South Texas. Each ranch had six 81 ha high-fenced enclosures. On each ranch, there were 2 enclosures with a goal of 10, 25, and 40 deer, respectively. They were considered low, medium and high density, respectively. One of each density level was provided pelleted supplemental feed year around. I used a panel of microsatellite DNA markers to test the effect of supplemental feed and population density on the distribution of male breeding success. Due to different recruitment rates between fed and unfed enclosures, I was not able to evaluate the effect of feed. Across all density levels, 80% of parentage assignments were mature (3.5+ years old) bucks. In the high density fed enclosures, only 1 1.5-year-old male sired a fawn. My results suggest that competition among males for breeding access may increase with population density. Additional years of data collection are needed to determine if supplemental feed affects male breeding success in white-tailed deer.