Predator recognition and nest defence by Carolina Wrens Thryothorus ludovicianus in urban and rural environments: does experience matter?

Abstract

ABSTRACTCapsule: Carolina Wrens Thryothorus ludovicianus in urban and rural environments responded most intensely to predators common to their environments.Aims: To determine the role of experience in predator recognition and response among Carolina Wrens. We predicted that wrens in the urban environment, where domestic cats are common, would respond more intensely to mounts of cats than snakes (a less common nest predator) placed near their nests. In the rural (forested) environment, we predicted a greater response to snakes than cats, because snakes are the more common predator in that environment.Methods: We placed mounted specimens of a snake and a cat near wren nests at the late nestling stage and quantified responses. We used a Rock Dove Columba livia mount as the control because it is a non-threatening species to the nestlings, and should be familiar to the wrens.Results: Carolina Wrens in the urban area responded most intensively to the cat mounts, whereas those in the rural environment responded more to the snake, with indications of innate predator recognition and defence. Cats were more common in the urban environment. Wrens used different alarm calls in the two habitats, but further study is needed to understand the significance of this variation.Conclusions: Birds may have the ability to adapt their responses to local predators, both native and non-native, which may be especially important for their success in urbanized habitats.