Autumn roost-site selection by male hoary bats (Lasiurus cinereus) in northern California

Abstract

Abstract Effective conservation and management of a species relies upon understanding its habitat throughout its full annual cycle. For hoary bats, Lasiurus cinereus, their ecology is largely known from summer with the exception that they move long distances during autumn and spring and maintain some level of activity year-round. Autumn is a critically important period for hoary bats as they complete long-distance migrations between summer and winter range and they mate, both of which are energetically expensive. We studied hoary bat roost selection during autumn in a migratory stopover area in redwood habitat in northwestern California. We hypothesized that hoary bats select day roosts during autumn migration that minimize energetic expenditures and improve mating opportunities. We located 24 day roost sites of male hoary bats and evaluated site-level roost selection by comparing roosts with 120 random locations. We used multiple logistic regression to compare remotely sensed habitat features derived from LiDAR and other spatial data. The three most important variables for distinguishing roost from random locations were distance to creek, roads, and meadow. We speculate that selection of roosts in proximity to open spaces and flyways facilitated social behaviors related to mating that are commonly observed in this area.