Frank J. Bonaccorso Corinna A. Pinzari Christopher M. Todd Kristina Montoya-Aiona Kevin W. Brinck Marcos P. Gorressen 2013 Using acoustic recordings of the vocalizations of the endangered Hawaiian hoary bat (<i>Lasiurus cinereus semotus</i>) collected over a five-year period (2007–2011) from 25 survey areas across the island of Hawai`i, we modeled the relationship between habitat attributes and bat occurrence. Our data support the conclusion that hoary bats concentrate in the coastal lowlands of Hawai`i during the breeding season, May through October, and migrate to interior highlands during the winter non-breeding season. Highest occupancy peaked on the Julian date 15 September across the five-year average and during the season of fledging by the young of the year. Although the Hawaiian hoary bat is a habitat generalist species and occurs from sea level to the highest volcanic peaks on Hawai`i, there was a significant association between occupancy and the prevalence of mature forest cover. Trends in occupancy were stable to slightly increasing during the breeding season over the five years of our surveys. application/pdf en University of Hawai‘i at Hilo A five-year study of Hawaiian hoary bat (<i>Lasiurus cinereus semotus</i>) occupancy on the island of Hawai`i reports