Figure 1.

Diagrams of the two chorusing sites. On each diagram, the two black square∕white cross symbols outside of the pond outline indicate the position of the two acoustic sensors. (A) Map of pond 1 showing estimated locations and numbers of actively calling bullfrogs (designated by open circles with numbers) on the night of 6∕12∕05. Each circle is placed at the median of the vector intersection points derived from the computational model. Only one bullfrog was present at each indicated location. Locations are numbered in the order in which they were identified in the analysis. (B) Map of activity at pond 1 on the night of 7∕5∕05. Five vocalizing bullfrogs were now present at location 2. (C) Map of pond 2. The locations of bullfrogs were similar on all three nights (7∕5∕06, 7∕6∕06, and 7∕9∕06) at this site; the variability in numbers of animals at each location is indicated. On all three nights, location 4 contained only one bullfrog.