The following article is available for download by list members at
http://www.uvm.edu/~bmitchel/Bioacoustics.html.
Hayes, Ashley R., and Nancy J. Huntly. 2005. Effect of wind on the
behavior and call transmission of pikas (Ochotona princeps). Journal of
Mammalogy 86(5):974-981.
Abstract:
It has been suggested that pikas are less active during inclement
weather. We hypothesized that this decrease in activity is a
predator-avoidance response to wind conditions that decrease the
effectiveness of the alarm calls of pikas. We examined this hypothesis
by broadcasting and rerecording the prominent frequencies
(900–5,500 Hz) of pikas' calls and by observing behavior of focal
pikas during varying weather conditions. Both attenuation of pure
tones and the amount of wind noise increased significantly as wind
speed increased. Additionally, wind direction created asymmetrical
patterns of attenuation of pure tones, potentially distorting and
degrading the call. Further, pikas spent significantly more time
inactive at higher wind speeds, with nonvigilant active behaviors
decreasing at a higher rate than vigilant active behaviors.
Examination of these data supports the hypothesis and suggests that
wind influences the behavior of animals that rely on alarm calls.
Brian R. Mitchell
|