A technique to estimate white-tailed deer Odocoileus virginianus density using vertical-looking infrared imagery

Abstract

Aerial infrared imagery is used increasingly in eastern North America to provide population counts of white-tailed deer Odocoileus virginianus because of the increased probability of detection compared to visual methods. To date, most work using infrared technology has been conducted using imagery from Forward-Looking Infrared (FLIR). Methods have produced counts, but density or population estimates have not been forthcoming because of problems with methodology and automation. Using standard photogrammetry techniques, Vertical-Looking Infrared (VLIR) data, GIS and distance sampling, we describe a method for estimating density. We estimated deer density in four bottomland hardwood sites in Arkansas, USA, with distance sampling using VLIR data and assessed the probability of detection of deer identified in the imagery. Uniform models were selected as the best representative models for each site, and probability of detection was similar (x? = 0.95 ± 0.05 SE) across sites. Distance sampling used in conjunction with VLIR data may provide estimates of ungulate populations in ecosystems of deciduous hardwoods with little topographic relief. © Wildlife Biology, NKV.