Use of Infrared Technology in Wildlife Surveys

With the exception of trapping-based methods, quantification of wildlife populations has traditionally involved counts of animal sign (e.g., nests, scat, or calls) or cues (e.g., breeches by marine mammals) as indices, or counts of individual animals or groups (i.e., direct counts). In addition to the “naked” eye, researchers have used binoculars, spotlights, and more recently, night-vision and infrared technology (IT) to aid direct counts. However, IT has become a standard tool in a variety of practices (e.g., industrial, law enforcement, veterinary medicine) because any material with a temperature above absolute zero (i.e., -273.3°C) emits infrared light (i.e., the electromagnetic spectrum >0.70 μm), which can be quantified. The application of IT to wildlife management and research allows one to discern infrared emissions from target animals against background vegetation or habitat and, therefore, offers an improvement over traditional sighting methods. Use of IT in wildlife surveys also has inherent logistical requirements that must be considered in survey design. The purpose of this paper is to provide insight into the application of IT in wildlife management and research, particularly as related to quantifying populations of wildlife active during the night or periods of low-light conditions. Our objectives are to 1) briefly review methods and assumptions associated with conducting wildlife surveys, 2) review research and management efforts that have incorporated IT in surveys of wildlife populations, 3) discuss new opportunities for the incorporation of IT into wildlife research and management, and 4) provide guidance on purchasing IT. We suggest that IT, in combination with valid scientific sampling methods, can potentially increase the ability of wildlife researchers and managers to accurately estimate densities of wildlife populations.