Disturbances to animals can cause changes in behavior. Therefore, it is critical for wildlife managers to understand what disturbances may impact animals and how animals adapt to them. USGS scientists analyzed the relationship between human-based disturbance and animal movement and habitat use. Fifteen dabbling ducks were tracked with GSM-GPS units for ~4 weeks before, during, and after the start of a recreational hunting season in October/November 2018. Animal locations were recorded every 2 minutes across three separate 24-hour tracking phases: Phase 1) two weeks before the start of the hunting season (control (undisturbed) movement); Phase 2) the hunting season opening weekend; and Phase 3) a hunting weekend two weeks after opening weekend. The 24-hour tracking phases were divided into three levels of disturbance related to the time of day: high (lethal human active (hunting)/~daytime); moderate (non-lethal human active/ ~crepuscular); and low (nighttime).
The results showed that during opening weekend flight (% time and distance) more than doubled during moderate (non-lethal human active) and low (nighttime) disturbance and increased by ~50% during high (lethal human active (hunting)) disturbance compared with the pre-season weekend. Sanctuary (non-hunted areas) use increased by three times during moderate and low disturbance and increased ~50% during high disturbance. Two weeks later, flight decreased in all disturbance levels but was only less than the pre-season levels during high disturbance. In contrast, sanctuary use only decreased at night while daytime doubled from ~45% to more than 80%, although not to pre-season levels. Ducks adjusted rapidly to disturbance.
A graphical overview of the duck disturbance study shows the project design, implementation, and statistical analysis; results for different disturbance levels; and implications for duck flight patterns, energetic demands, and wetland habitat use.