The fringe-lipped bat, Trachops cirrhosus, is an eavesdropping predator that hunts frogs and katydids by approaching these preys' sexual advertisement calls. In captivity, bats can rapidly learn to associate novel acoustic stimuli with food rewards. It is unknown how this learning ability is related to foraging behavior in the wild where prey and the calls that identify them vary over space and time. In two bat populations that differ in available prey species (Soberania, Panama, and La Selva, Costa Rica), we presented wild-caught bats with frog calls, katydid calls, and control stimuli. Bats in Soberania were significantly more responsive to complex calls and choruses of the tungara frog, Physalaemus pustulosus, than were bats in La Selva. La Selva bats were significantly more responsive to katydid calls (Steirodon sp.) than Soberania bats. We also examined seasonal variation in bat response to prey cues. Bats were captured in Soberania in dry and wet seasons and presented with the calls of a dry season breeding frog (Smilisca sila), a wet season breeding frog (P. pustulosus), and four katydid species. Bats captured in the dry season were significantly more responsive to the calls of S. sila than bats captured in the wet season, but there were no seasonal differences in response to the calls of P. pustulosus or the katydid calls. We demonstrate plasticity in the foraging behavior of this eavesdropping predator but also show that response to prey cues is not predicted solely by prey availability.