5aAB3. Performance of desert kit foxes, Vulpes macrotis arsipus, on acoustic detection trials during simulated jet aircraft overflights.

Session: Friday Morning, May 17

Time: 8:45

Author: Ann E. Bowles
Author: Scott Yaeger
Location: Hubbs-Sea World Res. Inst., 2595 Ingraham St., San Diego, CA 92109
Author: B. Andrew Kugler
Location: BBN Systems and Technologies Corp., Canoga Park, CA 91303
Author: Richard Golightly
Location: Humboldt State Univ., Arcata, CA


Two male and female desert kit foxes were exposed to simulated prey and predator sounds in the presence of aircraft noise to determine detection rates. They were tested in a 9.75x9.15-m outdoor pen in the dark. Five feeding stations were equipped with speakers to play scratching sounds (prey noise) and a single speaker outside the pen projected stealthy footsteps (predator noise). Foxes approached feeding stations projecting prey noise to receive a reward; they spontaneously avoided predator noise. Foxes were exposedto 980 simulated low-altitude jet overflights in the range from 65 to 95 dB ASEL. Stimulus sounds were played for 1 min at the limit of detection; the longest simulated overflight was 45 s. Fox performance was compared with and without simulated aircraftnoise (309 and 110 trials, respectively). Foxes exhibited flight reactions or dropped flat during initial exposures. Within 1--2 series of exposures, these responses habituated, although milder reactions persisted. Foxes identified the correct feeding station 63%--71% of the time (chance rate=20%) in silence versus 24%--30% in noise. They detected predator sounds on 81%--83% of trials, regardless of noise. The results suggest that foxes listened for potential predators preferentially in the presence of aircraft noise. [Work supported by USAF NSBIT Program, Contract F33615-90-D-0653.]

from ASA 131st Meeting, Indianapolis, May 1996