Hawaiian hoary bat roost departure-arrival metrics, Hawaii Island 2018-2019

Hawaiian hoary bats (Lasiurus cinereus semotus) were captured at multiple locations on the east side of Hawaii Island from May 2019 to October 2019. Radio transmitters were affixed to captured bats and, when possible, radio telemetry was used to locate bats in trees used for day-roosts. In 2019, three maternity roosts were identified however only two were suitable for video recording. Thermal video recording at two maternal roosts was used to identify the time of bat departure and arrival at a roost. We examined an average of 2 hours during sunset and sunrise (range = 0.9 to 5.4 hours). The time of bat departure from a roost ranged from 53 minutes before sunset to 20 minutes after sunset (n = 48, mean = 2.7 minutes before sunset). The time of bat arrival at roost ranged from 41 minutes before sunrise to 11 minutes before sunrise (n = 40, mean = 22 minutes before sunrise). Departure and arrival times were positively correlated (r = 0.16); that is, earlier departures were generally associated with earlier arrivals at a roost the following morning. No potential predators (cats or rats) were seen during the period of video review.

[
  "010:12"
]

[
  "geospatial"
]