U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

February 2006


Published in The Journal of Wildlife Management - 70(6).


Aerial telemetry is commonly used to locate wildlife in remote areas (Gilmer et al. 1981, White and Garrott 1990, Samuel and Fuller 1996). If locations are used to determine home range, habitat use, or similar parameters, error associated with locations must be estimated (Cederlund et al. 1979, Laundre et al. 1987, White and Garrott 1990, Carrel et al. 1997).

Typically, aerial locations are subject to 2 sources of error. If the transmitter-equipped animals are not sighted from the aircraft, their ground location must be estimated. Then, the estimated ground location must be identified on a map and recorded. The combined effect of both errors can be influenced by several variables including the relative sensitivity of the paired antennas, antenna mounting systems that can influence the radio signal, air turbulence, terrain, map quality, and observer experience and familiarity with the study area (Hoskinson 1976, Cochran 1980). When transmitter-equipped animals are visually located from the aircraft (Mech 1983), the first error source is eliminated. However, visual location is frequently hampered by ground cover, animal size, cryptic coloration or behavior of the animal, and constraints dictated by flight time or safety.