Evaluation of portable infrared cameras for detecting Rio Grande wild turkeys

Observing nocturnal, cryptic, highly mobile, or elusive wildlife in the field is difficult. Precise abundance estimates are necessary to make management decisions. Numerous methods have been examined to estimate wild turkey abundance with limited success. The use of forward-looking infrared (FLIR) technology has increased and may improve the detection of wildlife. We sought to estimate Rio Grande wild turkey (Meleagris gallopavo intermedia) abundance using FLIP surveys and to assess the accuracy of these estimates by comparing them with independent estimates from ground surveys. We conducted 8 ground and aerial FLIP surveys of roost sites in 3 distinct ecological regions of Texas, USA. We were unable to aerially detect roosting turkeys using the portable FLIP camera because of altitudinal restrictions required for safe helicopter flight and lack of thermal contrast Flight altitude was a principal obstacle because topography and aerial obstructions (i.e., utility poles, towers, and wires) often required higher-altitude flights than ideal for turkey observation. From an aerial perspective, wild turkey thermal signatures were camouflaged by their surroundings. The external temperatures of turkeys, tree branches, and other background objects (e.g., rocks, bare ground) were within 1.5 degrees C of each other despite ambient temperatures or other weather variables (i.e., wind speed, humidity, and cloud cover). Therefore, there was not sufficient difference in radiant temperature of a turkey and its background to permit adequate detection from an aerial perspective.