SOLAR ECLIPSE HAS NO DISCERNIBLE EFFECT ON BAT ACTIVITY

Anecdotal accounts of observations made during solar eclipses suggest that many animals exhibit atypical activity during and following an eclipse. This atypical behavior is expected because the rarity of a solar eclipse ensures that most animals never experience this novel event and thus it evokes novel behaviors. However, few data concerning the activity patterns of bats surrounding an eclipse are available to infer the influence of an eclipse on bat activity. Bats may perceive the daytime change in luminosity 1) as dusk and emerge from torpor in preparation for feeding, 2) similarly to changes in luminosity associated with weather events such as an impending thunderstorm or, 3) as a novel event that warrants an atypical response. Our objective was to determine the influence of a solar eclipse in northern Georgia on the nocturnal activity of bats following the eclipse. Specifically, we wanted to determine if activity was appreciably different from normal during the night following the eclipse in relation to 1) overall activity and 2) temporal distribution of activity during the night. To achieve our objective, we used an Anabat SD2 bat detector to record calls throughout the night following the eclipse and five subsequent nights. We recorded 532 call files during the 21-26 August 2017 sample period. Bat activity during the night following the eclipse was higher than average (105 vs. 89 call files recorded) and was concentrated more at the beginning of the night than average, which may have been related an increased energetic burden of emerging from diurnal torpor earlier than or more frequently than normal. However, call activity of bats is highly variable and neither deviation from normal was substantial enough for us to deem it biologically significant and attributable to the solar eclipse