VOCAL INTERACTIONS IN BUFO-WOODHOUSII-FOWLERI

I investigated acoustic interactions in Bufo woodhousii fowleri by using playbacks to simulate a vocal intrusion on a male's calling site. In response to intruder calls, males did not change their call rate, call duration, calling effort, pulse repetition rate, dominant frequency, or bandwidth, but they did shift the timing of their calls to avoid overlap. The amount of time that male calls were overlapped by intruder calls was significantly less than expected, and males tended to call sooner after the end of an intruder call than expected if timing was random. Males also significantly reduced their calling efforts during a silent period that followed playback of intruder calls. This suggests that behavior of a calling male is contingent on activity of local competitors and not on the chorus as a whole. Males did not change call parameters to match those of the intruder call.