Monitoring bats at Offutt Air Force Base reveals reduced bat activity near LED lights

Presenter Type

UNO Undergraduate Student

Major/Field of Study

Environmental Studies

Other

Environmental Science: Life Sciences

Advisor Information

Research Advisor

Location

MBSC Ballroom Poster # 706 - U

Presentation Type

Poster

Start Date

24-3-2023 1:00 PM

End Date

24-3-2023 2:15 PM

Abstract

Insect-eating bats are a critical component of ecosystems and a top-down control of many crop pests in agricultural regions. Despite the many benefits of these species, there are situations where their presence may cause issues at the human-wildlife interface. Offutt Air Force Base in Sarpy County, Nebraska is one such area that is looking for deterrence of bats from high traffic sites such as runways to avoid aircraft collisions with bats. Light-emitting diode (LED) security lights already in place around buildings and the runway at Offutt provide a potentially low-cost method to reduce bat activity near these areas. To determine whether the current artificial light at Offutt reduces bat activity, we used acoustic detectors (SM4BAT FS detectors with SMM-U2 ultrasonic microphones, Wildlife Acoustics) to record echolocation calls of free flying bats near lights and away from lights. Six detectors were paired at different sites in light and dark areas away from trees and water to keep habitat generally constant while varying light levels. Bat activity was recorded from 6 to 11 July and again from 12 to 18 July 2021. We used Wildlife Acoustic’s Kaleidoscope program to identify bat passes and quantified the number of passes per hour for each species. Our results showed that bats were more active in dark than light sites. The decrease in activity was consistent at all 6 sites and for all 3 bat species most commonly recorded at our sites, which included big brown bats, silver-haired bats, and hoary bats. Reduction in activity near lights was 34% for hoary bats, 50% for silver-haired bats, and 70% for big brown bats. Our results indicated that bright LED lights in open areas reduced activity of bats and might be useful as a deterrent in these situations. Few studies in North America have investigated the impact of artificial light on bats and continued research is critical to understand this aspect of bat activity in urban environments. Further research could investigate the effects of light properties (intensity, type, etc.) on bat activity and the type of bat activity. Our current research looks further into foraging behavior by screening our current data for feeding buzzes (a type of call unique to insect hunting in bats) to create a better understanding of what bats are doing at light and dark sites.

Scheduling

1-2:15 p.m., 2:30 -3:45 p.m.

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Mar 24th, 1:00 PM Mar 24th, 2:15 PM

Monitoring bats at Offutt Air Force Base reveals reduced bat activity near LED lights

MBSC Ballroom Poster # 706 - U

Insect-eating bats are a critical component of ecosystems and a top-down control of many crop pests in agricultural regions. Despite the many benefits of these species, there are situations where their presence may cause issues at the human-wildlife interface. Offutt Air Force Base in Sarpy County, Nebraska is one such area that is looking for deterrence of bats from high traffic sites such as runways to avoid aircraft collisions with bats. Light-emitting diode (LED) security lights already in place around buildings and the runway at Offutt provide a potentially low-cost method to reduce bat activity near these areas. To determine whether the current artificial light at Offutt reduces bat activity, we used acoustic detectors (SM4BAT FS detectors with SMM-U2 ultrasonic microphones, Wildlife Acoustics) to record echolocation calls of free flying bats near lights and away from lights. Six detectors were paired at different sites in light and dark areas away from trees and water to keep habitat generally constant while varying light levels. Bat activity was recorded from 6 to 11 July and again from 12 to 18 July 2021. We used Wildlife Acoustic’s Kaleidoscope program to identify bat passes and quantified the number of passes per hour for each species. Our results showed that bats were more active in dark than light sites. The decrease in activity was consistent at all 6 sites and for all 3 bat species most commonly recorded at our sites, which included big brown bats, silver-haired bats, and hoary bats. Reduction in activity near lights was 34% for hoary bats, 50% for silver-haired bats, and 70% for big brown bats. Our results indicated that bright LED lights in open areas reduced activity of bats and might be useful as a deterrent in these situations. Few studies in North America have investigated the impact of artificial light on bats and continued research is critical to understand this aspect of bat activity in urban environments. Further research could investigate the effects of light properties (intensity, type, etc.) on bat activity and the type of bat activity. Our current research looks further into foraging behavior by screening our current data for feeding buzzes (a type of call unique to insect hunting in bats) to create a better understanding of what bats are doing at light and dark sites.