The breeding calls of frogs and toads serve to attract females and advertise the fitness attributes of individual males, but male frogs will also call outside the breeding season. Here, we document non-reproductive (upland) calling in Crawfish Frogs (Lithobates areolatus), a species of conservation concern. Adults are obligate crayfish burrow dwellers and generally live in isolation. We document post-breeding upland call characteristics and identify peak upland seasonal calling times. We show that Crawfish Frog upland and breeding call spectral and temporal structures differ, suggesting these calls serve different functions. We also show that the transition between these distinct call types can occur within a relatively short time, 120 min, as Crawfish Frog males leave their burrows to begin breeding migrations. We demonstrate that upland calling rates increase as the summer progresses and that males call in response to specific stimuli-results consistent with a burrow defense hypothesis. Further, 28 (51%) of the 55 upland calling bouts we recorded were associated with human-generated triggers, including the sounds of airplanes and automobiles, a finding confirmed using playback experiments. Calling in response to noise pollution can increase exposure to predators, and we discuss the conservation implications of this action for this imperiled species.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science
- Animal Science and Zoology