Damm, P.E., Grand, J.B. Grand, and S.W. Barnett. Variation in detection among passive infrared triggered-cameras in wildlife research. Proceedings Southeastern Association of Fish and Wildlife Agencies.
Precise and accurate estimates of demographics such as age structure, productivity, and density are necessary in determining habitat and harvest management strategies for wildlife populations. Surveys using remote cameras are becoming an increasingly popular tool for estimating these parameters; however, most camera studies fail to incorporate detection and therefore underestimate these parameters. Thus, they underestimate the parameters of interest. The objective of this study was to determine the sources of heterogeneity in detection for trail cameras that incorporate a passive infrared (PIR) triggering system sensitive to heat and motion. Images were collected at four baited sites within the Conecuh National Forest, Alabama using three identically oriented cameras at each site operating continuously over the same seven-day period. Detection was estimated for four groups of animals based on taxonomic group and body size. Our hypotheses of detection considered variation among bait sites and cameras. The best model (wAICc = 0.99) estimated different rates of detection for each camera in addition to different detection rates for four animal groupings. Factors that explain this variation might include poor manufacturing tolerances, variation in PIR sensitivity, animal behavior, and species specific infrared radiation. Surveys using trail cameras with PIR systems must incorporate detection rates for individual cameras. Incorporating time-lapse triggering systems into survey designs should alleviate issues associated with PIR systems.