Monitoring the Behavior of Desert Ungulates by Acoustic Telemetry
Investigators (most current known information)
Accurate insights on feeding and other behaviors are essential for informed management of free-ranging desert wildlife. Owing to their wariness and to habitat constraints, however, it is virtually impossible to closely monitor detailed feeding and other behaviors of wildlife subjects by visual observation. This pioneering project sought to develop and implement an acoustic telemetry system for monitoring feeding, drinking, and other detailed behaviors of two representative desert ungulates by sound. The study species were desert mule deer in the U.S. and Nubian ibex in Israel. Principal phases of study included: (a) recording the behaviors of captive animals audio-visually; (b) initial characterization and analysis of sound signals generated by captive animals; (c) testing of alternative components and attachment sites of an acoustic telemetry system; and (d) assembling and testing a field-worthy acoustic system for monitoring free-ranging desert ungulates.
Using commercially available components we recorded a wide range of behaviors of captive deer and ibex, including feeding on a variety of forages. We obtained the highest quality sounds when the microphone was attached to the heads of test animals, as opposed to a collar-mounted configuration. Using domestic livestock we developed a simple surgical technique and non-surgical method for microphone attachment. We found that nearly all behaviors and food types could be reliably identified and enumerated on the basis of audible criteria by human hearing alone. We also undertook three ¿objective¿ computer-based analyses of feeding sounds generated by captive mule deer to explore the potential for machine-classification of behaviors by sound. Using a variety of software, we compared food types according to (1) elapsed time between sound impulses (ETBI), (2) frequency response functions (FRF), and (3) linear predictive coding (LPC) of audio energy peaks. The analyses detected some consistent differences among food types, but demonstrated that automatic classification and enumeration of such behaviors will require additional development. We also developed components of a field-worthy acoustic telemetry system. The transmitter consists of a small microphone attached to a shaved patch on the rear of the animal¿s head that is connected by a protected cable attached by tag cement to the animal¿s neck and leading to a collar mounted weather-proof transmitter package that is powered by two D-cell batteries. Estimated continuous operating time of the audio transmitter is = 3 weeks. Main components of the receiver station include a yagi or omnidirectional antennae mounted on a 20-ft telescopic mast, a 12-volt lead acid battery recharged by a solar panel, preamplifier, amplifier and receiver, and a ruggedized laptop computer with sound card and audio signal software that serves as the central data collection and processing center. The tested range of the receiver is nearly 2 kms with the yagi antenna. The system is transportable in a field vehicle and can be erected in 30 minutes.
At the conclusion of the study, we had completed arrangements for field application of the system on wild Nubian ibex in Israel and on free-ranging livestock at the Jornada Experimental Range, New Mexico. The tests will be conducted in July 2003.
Articles in Journals
Nelson, D.E., P.U. Alkon and P.R. Krausman. 2005. "Using acoustic telemetry to monitor foraging behavior by penned mule deer." Wildlife Society Bulletin (in press).
Nelson, D.E., P.U. Alkon and P.R. Krausman. 2003. "Monitoring mule deer feeding behavior by acoustic telemetry." AZ-NM annual joint Wildlife Society meeting. Gallup NM.
Nelson, D.E. 2003. Use of acoustic telemetry to monitor behavior of desert mule deer (Odocoileus hemionus erimicus). M.S. Thesis. The University of Arizona. Tucson AZ.