INFRARED-TRIGGERED CAMERAS FOR CENSUSING WHITE-TAILED DEER

Deer management often is hindered by lack of public acceptance and con fidence in census methods. Because ''seeing is believing,'' a method r elying on photographic documentation could provide a powerful tool for deer managers. The purpose of our study was to determine if infrared- triggered cameras could be used for population estimation of free-rang ing antlered white-tailed deer (Odocoileus virginianus) in a forested environment. Subsequently, we evaluated feasibility of using such esti mates in conjunction with demographic ratios for population estimation . We used infrared-triggered cameras and monitors to census white-tail ed deer on Longleaf Farms, a 4,047-ha area in Amite County, Mississipp i. Two 14-day censuses were conducted, 1 in February 1992 and 1 in Feb ruary 1993. Passive infrared monitors that triggered automatic cameras were used to photograph deer; previously marked deer in the photograp hs provided recapture data. We derived population estimates from photo graphs using Lincoln-Petersen Index estimates from marked and unmarked animals, and from a separate technique we termed the camera estimate. The camera estimate was calculated by determining the total numbers o f branch-antlered bucks, spike bucks, does, and fawns in photographs, then determining the number of individually identifiable branch-antler ed bucks and, from ratios, the number of spike bucks, does, and fawns. Camera densities tested included 65, 130, and 259 ha per camera. With the highest camera density (1/65 ha), 30 of 30 collared deer (100%) w ere recaptured in 1992 and 30 of 34 (88.2%) were recaptured in 1993. C amera estimates using ratios of spikes, does, and fawns to branch-antl ered bucks yielded population estimates of 715 and 580 deer for 1992 a nd 1993, respectively. Lincoln-Petersen estimates yielded 727 and 573 deer for the same respective periods. However, at different camera den sities, the sex ratios and Lincoln-Petersen Index population estimates differed significantly (P less than or equal to 0.001). There was an inverse relationship between camera density and Lincoln-Petersen Index population estimates. Percent females increased as camera density inc reased, indicating higher recapture estimates of males over females at low camera densities. Although population and sex-ratio estimates dif fered among camera-station densities, infrared-triggered cameras are u seful tools to census deer in forested environments. Minimally, they p rovide estimates of adult bucks present. Cost of a 14-day census amort ized over a 5-year equipment life expectancy ranged $0.37-1.29/ha/year depending on camera coverage.