Hawaiian hoary bat occupancy at Kaloko-Honokōhau National Historical Park

Hawaiian hoary bat (Lasiurus cinereus semotus) vocalizations were recorded using Anabat SD1 and Song Meter SM2Bat ultrasonic recorders at four monitoring stations in Kaloko-Honokōhau National Historical Park on the island of Hawai‘i. We hypothesize that echolocation call events are more numerous during the reproductive season of this bat. Bat detectors recorded from 1700 to 0730 hrs on a total of 42 nights between October 2011 and September 2012. Peak activity occurred between 1800 and 2000 hrs, although in May a secondary peak occurred between 0100 and 0300 hrs. Detectability proportions (0 to 1.0) were calculated using the software program PRESENCE (v4.2) and reported for each seven day recording session which was repeated on a bimonthly schedule. Hawaiian hoary bats were present in four of the six bimonthly surveys: January, May, September, and October; however, no bat calls were detected in March or July. Detectability of bat calls was above 0.50 in January, May, and September. Foraging buzzes, indicating feeding activity, were recorded in all months that bats were present.