Form Submission: Participation Entry

Predation risk and prey fear responses to predators are well-established concepts in animal behavioral ecology. What remains uncertain is how spatial variation in risk effects and abiotic factors translates into spatial variation in prey occurrence. To address this lack in understanding, we report on an analysis of ptarmigan (Lagopus sp.) spatial responses to predation risk from their primary predator the gyrfalcon (Falco rusticolus) in an Alaskan tundra landscape, including both biotic and abiotic factors. We examined the spatial responses of rock ptarmigan (L. muta) and willow ptarmigan (L. lagopus) at different distances from gyrfalcon nests across the study region. We also examined environmental variables in our analysis, as gyrfalcons use the physical conditions of the landscape to aid in hunting success. As predicted, ptarmigan were spatially distributed at increasing distances from gyrfalcon nests. Ptarmigan also responded to spatial risk with changes in behavior and were more likely to be seen hiding under shrubs when closer to gyrfalcon nests. However, ptarmigan were not located uniformly at large distances from gyrfalcon nests. Our data demonstrated that when selecting areas of low predation risk, ptarmigan prefer sites that are protected from wind but show high wind speeds in the sky above. This selection allows for better thermoregulation in the face of wind chill, but it also increases the difficulty of a successful attack for a falcon. We conclude that ptarmigan balance a number of factors to achieve the lowest possible risk of death from their most prolific predator, exhibiting differences in spatial distribution, behavioral plasticity, and responsiveness to abiotic variables to defend against the expression of multiple functional traits of predation.