Habitat use, diet, prey availability and foraging ecology of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus, Vespertilionidae), was examined in the east Maui region inclusive of the Waihou Mitigation Area, Pu‘u Makua Restoration Area. Research funding was provided by Auwahi Wind Energy, LLC, in order to fulfill its requirements for mitigating bat fatalities under its approved incidental take permit. Acoustic monitoring over the three-year period demonstrated that bats are present and actively feed year-round at the Waihou Mitigation Area. A comparison of simultaneous recordings between SM2 acoustic detectors equipped with SMX-US and newer SMX-U1 ultrasonic microphones was performed to assess whether the detection data from the older SMX-US could be corrected and made comparable to that obtained from SMX-U1. The test was conducted at two stations (AUW4 and AUW5) between October 14th and November 27th, 2016. The SM2 detectors at each of the two stations were equipped with an SMX-US and an SMX-U1 positioned at the same height above ground and aimed into the same airspace.