Spatiotemporal predictions of the alternative prey hypothesis: Predator habitat use during decreasing prey abundance

The alternative prey hypothesis supposes that predators supported by a
primary prey species will shift to consume alternative prey during a
decrease in primary prey abundance. The hypothesis implies that during
declines of one prey species, a predator modifies their behavior to
exploit a secondary, or alternative, species. Despite occurring in many
systems, the behavioral mechanisms (e.g., habitat selection) allowing
predators to shift toward alternative prey during declines in the
abundance of their primary prey are poorly understood. We evaluated
habitat selection and use by a generalist predator with respect to two
prey species during a dramatic decrease in the abundance of primary prey.
Further, we evaluated how spatial variation in access to primary prey
affected habitat selection and assessed similarity and overlap between
habitats used by each prey species. Coyotes (Canis latrans) exhibited
decreasing selection for cottontail rabbits (Sylvilagus spp.; primary
prey) during population decreases but did not shift habitat selection
toward neonate mule deer (Odocoileus hemionus; alternative prey). Use of
rabbit habitat remained high even during historically low rabbit
abundance, while mule deer habitat was used in proportion to its
availability. Coyotes seemingly do not make large shifts in habitat
selection toward alternative prey following spatial and temporal decreases
in the abundance of primary prey, but instead, take advantage of habitat
overlap to facilitate prey-switching behavior. Our work extends previous
research conducted under the alternative prey hypothesis by explicitly
evaluating the influence of habitat overlap between prey species and
variation in access to prey habitat as factors affecting prey-switching
behaviors in predators.