Large trees and forest heterogeneity facilitate prey capture by California Spotted Owls

Predators are among the most threatened animal groups globally, with prey declines contributing to their endangerment. However, assessments of the habitat conditions that influence the successful capture of different prey species are rare, especially for small, cryptic predators. Accordingly, most predator conservation plans are based on the relative importance of habitats inferred from coarse-scale studies that do not consider habitat features contributing to hunting success, which can vary among prey species. To address this limitation, we integrated high-resolution global positioning system tracking and nest video monitoring to characterize habitat features at prey capture locations during the nestling provisioning stage for the Spotted Owl (Strix occidentalis) a small, cryptic predator that has been at the center of a decades-long forest management conflict in western North America. When all prey species were considered collectively, males provisioning nests tended to capture prey: (1) in areas with more large-tree forest, (2) in areas with more medium trees/medium canopy forest, and (3) at edges between conifer and hardwood forests. However, when we considered the owl's two key prey species separately, males captured woodrats (Neotoma fuscipes) and Humboldt flying squirrels (Glaucomys oregonensis) in areas with markedly different habitat features. Our study provides clarity for forest management in mixed-ownership landscapes because different prey species achieve high densities in different habitat types. Specifically, our results suggest that promoting large trees, increasing forest heterogeneity, and creating canopy gaps in forests with medium trees/high canopy cover could benefit Spotted Owls and their prey, which has the ancillary benefit of enhancing forest resilience. Combining high-resolution global positioning system tagging with video-based information on prey deliveries to breeding sites can strengthen conservation planning for small predators by more rigorously defining those habitat features that are associated with successful prey acquisition. Lay Summary center dot Predators capture their prey where prey are both present and available for capture. Therefore, mapping and analyzing habitat at capture locations can aid management of quality habitat for predator conservation. center dot It is difficult to find the exact places where predators capture their prey. This is especially challenging for smaller, cryptic predators that do not leave behind obvious kill sites. center dot We attached global positioning system (GPS) tags to Spotted Owls and placed video cameras at their nests. We assessed the GPS movements to identify places they captured prey, which we then classified into species based on the video data. center dot Spotted Owls captured prey in places with big trees, with medium trees and medium canopy cover, and with a greater mixture of forest types (heterogeneity) and forest edge. center dot Forest management that promotes big trees, increases forest heterogeneity, and creates canopy gaps in forests will likely result in greater foraging success by owls, as well as increase forest resilience.