Understanding the interplay between weather conditions and nightly bat activity is important for interpreting acoustic monitoring data and identifying species-specific patterns in activity. We evaluated the relationship between weather variables and bat acoustic activity at 11 Wildlife Management Areas and State Park locations along the Missouri River corridor in North Dakota. Ten SM5 acoustic detectors were deployed at twenty-seven locations following U.S. Fish and Wildlife Service acoustic survey standards, and recorded calls were classified to species using Kaleidoscope Pro. Negative binomial mixed-effects models were used to assess relationships between nightly bat call activity and wind speed, minimum temperature, and precipitation measured at the nearest weather station.
Results showed that weather significantly influenced bat activity, although responses differed among species. Higher wind speeds were associated with increased activity in silver-haired bats (Lasionycteris noctivagans), while warmer minimum temperatures were associated with greater activity in silver-haired bats, eastern red bats (Lasiurus borealis), and big brown bats (Eptesicus fuscus). Precipitation was not a significant predictor of activity for any species evaluated. These results show that weather-related effects on bat activity are species-specific rather than uniform across the bat community. Accounting for environmental conditions during acoustic monitoring may therefore improve interpretation of temporal variation in bat detections.