U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

July 2002


Published in JOURNAL OF AVIAN BIOLOGY 33:3 (2002).


How predators locate avian nests is poorly understood and has been subjected to little experimental inquiry. We examined which sensory stimuli were important in the nest-finding behavior of fish crowsCorvus ossifragus, a common nest predator in the southeastern United States. Using an array of potted trees in a large enclosure, we presented artificial nests to captive crows and quantified responses to visual, auditory, and olfactory nest cues, and nest position. Partial ranks of nest-treatment preferences were analyzed using log-linear models. Nest visibility significantly increased the likelihood of predation by fish crows and increasing nest height was a marginally significant influence on nest vulnerability; no responses were apparent to auditory or olfactory stimuli. Our findings demonstrate that fish crows are visually-oriented nest predators that may preferentially prey on, or more readily encounter, above-ground nests. Moreover, the experimental design provides a new method for evaluating predator-prey interactions between nests and their predators. This study also illustrates how sensory capabilities of predators can interact with nest types to determine nest predation patterns.