THE INFLUENCE OF NATURAL SOUNDS ON CALIFORNIA GROUND SQUIRREL (OTOSPERMOPHILUS BEECHEYI) VIGILANCE AND PREDATOR DETECTION

My-Lan T Le; California Polytechnic State University; MYLAN.THI.LE@GMAIL.COM; Christopher, M, Garvin, Clinton, D, Francis

Many animals rely on the acoustical environment for essential functions including predator and prey detection. Research suggests environmental acoustics can greatly influence the propagation and reception of biologically relevant sounds, potentially interfering with the ability of animals to interact with their environment. We sought to determine whether natural sounds influence vigilance and predator detection in California ground squirrels. A field experiment recorded vigilance and foraging behavior under three noise playback conditions: river rapids, cicada chorus, and a silent control. Within each treatment, we measured flight initiation distance (FID), which is defined as the distance that an animal flees from an approaching threat. FIDs were measured using a robotic coyote to simulate a common predator in the study area. Squirrels were more vigilant during river rapids playback relative to control and cicada chorus treatments. We found mixed results regarding the influence of sound treatments on foraging rates and no difference in FIDs among the three treatments. To our knowledge, our results are the first to demonstrate that natural sounds can influence vigilance. Our results support recent studies demonstrating increased vigilance in the presence of low-frequency background noise from traffic or wind farms. Whether natural sounds influence other key behaviors is ripe for future studies.

Ecology and Conservation of Mammals IV     Student Paper