Appendix 6-1 Technical Report HCSU-089 HAWAIIAN HOARY BAT ACOUSTIC MONITORING ON U. S. ARMY O`AHU FACILITIES 1 1 2 Frank J. Bonaccorso , Kristin Montoya-Aiona , and Corinna A. Pinzari 1 U.S. Geological Survey, Pacific Island Ecosystems Research Center, Kīlauea Field Station, P.O. Box 44, Hawai`i National Park, HI 96718 2 Hawai`i Cooperative Studies Unit, University of Hawai`i at Hilo, P.O. Box 44, Hawai`i National Park, HI 96718 Hawai`i Cooperative Studies Unit University of Hawai`i at Hilo 200 W. Kawili St. Hilo, HI 96720 (808) 933-0706 This product was prepared under Cooperative Agreement G14AC00392 for the Pacific Island Ecosystems Research Center of the U.S. Geological Survey. This article has been peer reviewed and approved for publication consistent with USGS Fundamental Science Practices (http://pubs.usgs.gov/circ/1367/). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ii TABLE OF CONTENTS List of Tables ..................................................................................................................... iii List of Figures .................................................................................................................... iii Abstract ............................................................................................................................ 1 Introduction ...................................................................................................................... 1 Methods ............................................................................................................................ 2 Results .............................................................................................................................. 6 Bat Distribution and Presence .......................................................................................... 6 Seasonal Bat Activity ....................................................................................................... 7 Foraging Activity ............................................................................................................12 Discussion ........................................................................................................................13 Acknowledgements ...........................................................................................................14 Literature Cited .................................................................................................................15 Appendices .......................................................................................................................17 LIST OF TABLES Table 1. Hawaiian hoary bat survey effort on U.S. Army installations on O‘ahu. ....................... 4 Table 2. Summary of acoustic monitoring at 30 stations and 12 locations. .............................. 5 Table 3. Sampling effort by month 12 locations surveyed from 2015 through 2016. ................. 8 Appendix 2. Frequency of nightly bat detections by month and monitoring station. .................29 LIST OF FIGURES Figure 1. Locations of 30 acoustic detector stations on U. S. Army installations, O‘ahu Island. .. 3 Figure 2. Spectrogram of search-phase call pulses followed by terminal-phase series of pulses. 6 Figure 3. Confirmed bat presence or presumed absence from 2015 through 2016.. ................. 7 Figure 4. Mean frequency of bat detections during the reproductive and fledging periods........10 Figure 5. Total number of acoustic call events by time of night. ............................................11 Figure 6. Hawaiian hoary bat foraging activity in the Schofield East and West Ranges in 2015. 13 Appendix 1. Aerial maps and habitat of Hawaiian hoary bat acoustic monitoring stations. .......17 iii ABSTRACT Acoustic sampling for occurrence of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) was conducted at 12 locations on U. S. Army installations on O‘ahu Island, Hawai‘i. Bats were confirmed as present at 10 of these locations: Dillingham Military Reservation, Helemano Military Reservation, Kahuku Training Area, Kawailoa Training Area, Mākua Military Reservation, Schofield Barracks East Range, Schofield Barracks West Range, Schofield Barracks (Mendonca Park Housing), Tripler Army Medical Center, and Wheeler Army Airfield. Our acoustic sampling did not record bat vocalizations at Fort DeRussy or Fort Shafter. Despite the presence of bats at the above 10 locations, foraging activity as identified from characteristic feeding buzzes was observed only at East Range and West Range of Schofield Barracks. Nevertheless, Hawaiian hoary bats were recorded actively searching for prey in airspace at 10 of the 12 areas during important periods of Hawaiian hoary bat life history, including periods of pregnancy, lactation, and pup fledging. Within-night bat activity pooled for all nights and detectors at each location showed bat activity was mostly confined to the first several hours of the night. This acoustic study detected bats at lower rates of occurrence (frequency of detection [“f”] = 0.07) compared to detection probabilities (“dp”) observed on the islands of Hawai‘i (dp = 0.56) and Maui (dp = 0.27), implying either behavioral differences or that they occur at lower densities on O‘ahu. The rate is also consistent with results from two previous acoustic studies conducted on O‘ahu; a year long monitoring study in the northern Ko‘olau Mountains in 2014 (dp = 0.08), and short-term seasonal Army monitoring efforts in 2012 (dp = 0.05 to 0.06). INTRODUCTION Also known as the ‘Ōpe‘ape‘a, the Hawaiian hoary bat (Lasiurus cinereus semotus) is the only extant native terrestrial mammal and sole bat species in Hawai‘i state. This endemic subspecies of hoary bat occurs on all of the major islands (Tomich 1986) and is listed by the U.S. Fish and Wildlife Service (USFWS) and the State of Hawai‘i Department of Forestry and Wildlife list as “Endangered”. The species is a habitat generalist with aerial-hawking foraging behavior and feeds primarily on Coleoptera and Lepidoptera captured and eaten while in flight (Whitaker and Tomich 1983, Belwood and Fullard 1984, Jacobs 1999). Individual bats are highly mobile and regularly forage in multiple disjunct feeding areas that may be up to 15 km in long axis across an individual’s foraging range, as demonstrated in radio-telemetry studies conducted on both Hawai‘i and Maui islands (Bonaccorso et al. 2015, D. Johnston, H.T. Harvey and Associates, pers. comm.). Use of ultrasonic acoustic monitoring techniques have revealed this species’ seasonal presence and aspects of its behavior across many areas of the state (Gorresen et al. 2013, Pinzari et al. 2014, Todd et al. 2016); however, with the exception of Gorresen et al. 2015, there is relatively little published about populations and contemporary distributional range of this bat on O‘ahu. The objectives in this acoustic monitoring effort were to provide an assessment for U.S. Army facilities on O‘ahu of Hawaiian hoary bat occurrence and distribution during important life history periods, and evidence of foraging activity. 1 METHODS The study was conducted across 12 locations on U. S. Army installations on O‘ahu between 28 January 2015 and 23 March 2016 (Figure 1). We deployed SM2Bat+ Song Meter Digital Field Recorders (Wildlife Acoustics Inc., Concord, MA) capable of recording ultrasound between 10 and 100 kHz at 30 monitoring stations (Table 1). Each station consisted of a SM2Bat+in waterproof housing, 6V external battery, 6W solar panel, and SMX-US ultrasonic microphone (Wildlife Acoustics Inc., Concord, MA). Microphones were placed at the top of a metal conduit 2 to 3 m above the ground and connected by cable to the SM2Bat+ microphone port. These microphones are omnidirectional and capable of detecting bat calls at distances up to 30 m under ideal conditions (Adams et al. 2012). However, the range of call detection varies with weather conditions and orientation of the bat relative to the microphone. One to five stations per location, depending on Army installation size and accessibility, were placed in open areas or along vegetation edges (see Appendix 1) because Hawaiian hoary bats frequently fly and forage along edge/open areas and to ensure adequate sunlight to power solar panels and recharge batteries. Elevation at stations ranged between 1 and 552 m asl (Table 1). Stations were maintained for between 134 and 420 nights of recording (Table 2) except at Fort DeRussy, where a single station operated only for 53 nights because of technical and security issues. All sound files were recorded in the Waveform Audio File format (.wav) onto Secure Digital (SD) memory cards with corresponding times and dates. All detectors operated from one hour before local sunset until one hour after local sunrise. Recording units were checked at 2–3 month intervals to exchange SD data cards and test optimal battery and microphone function. 2 Figure 1. Locations of 30 acoustic detector stations (red dots) on U. S. Army installations, O‘ahu Island. 3 Table 1. Hawaiian hoary bat survey effort on U.S. Army installations on O‘ahu, including Universal Transverse Mercator (UTM) locations (Zone 4, datum WGS84), elevation, and operational dates for acoustic monitoring stations. Monitoring UTM UTM Elevation Installation Start Date End Date Station Easting Northing (m) Dillingham DIL1 583839 2386391 1 2/3/2015 9/24/2015 Military DIL2 582900 2385660 6 2/3/2015 9/24/2015 Reservation