Cooperative Fish and Wildlife Research Units Program: Headquarters
Education, Research and Technical Assistance for Managing Our Natural Resources

Monitoring waterfowl populations provides the basis for improving habitat quantity and quality, establishing harvest regulations, and ensuring sustainable waterfowl populations through components of state natural-resource management objectives, joint-venture objectives, and the North American Waterfowl Management Plan. Waterfowl biologists currently use a variety of population and habitat monitoring methods ranging from informal ground observations to more systematic approaches, including low-level crewed aerial surveys. Although uncrewed aerial systems (UAS) may provide safer and more precise alternatives to traditional aerial survey techniques that are less disturbing to waterfowl and safer for people and waterfowl, there is limited information on how waterfowl in winter respond to UAS. We compared the behavioral responses of waterfowl to helicopters and UAS on Missouri Department of Conservation wetland conservation areas flown during waterfowl surveys October – February 2021-2022. Helicopter surveys were flown using an Airbus H125 helicopter at heights of 100 – 350 meters, with UAS surveys flown using a DJI Mavic 2 Pro UAS at 15 – 90 meters. Waterfowl behavior was categorized using flock-scan surveys recorded for 10-minute periods before, during, and after the surveys. Behaviors were categorized as alert, swim, fly, or abandonment and the proportion of time flocks spent in each behavior during- or post-survey were compared to pre-survey behaviors. Waterfowl behavior increased time spent swimming, flying, and abandonment in response to helicopter flights, whereas UAS flights did not influence waterfowl behavior regardless of survey height, guild or hunting season (open or closed). UAS may be a good alternative to traditional survey methods and are not likely to affect waterfowl distributions or energy expenditures during the survey periods.