In response to a need for mitigating blackbird damage to crops, we evaluated the effectiveness of two unmanned aircraft systems (UAS or drones) to protect crops from blackbird damage. UAS are known to elicit behavioral and physiological responses in wildlife and have been proposed as a means to protect row crop agriculture from avian pest depredation. We evaluated the behavioral responses of captive and free-ranging red-winged blackbirds to a fixed-wing and a rotary-wing (multi-rotor, quadcopter) UAS by comparing preflight behaviors to behaviors during UAS approach. Due to the flight limitations of the respective UAS, the fixed-wing and rotary-wing were evaluated at different altitudes. Behavioral responses of captive and free-ranging blackbirds to approaching UAS were categorized as no response, alertness, or attempted escape/flight. Neither captive nor free-ranging flocks of red-winged blackbirds displayed behavioral responses to approaches by the fixed-wing UAS when flown at or above 52 m above ground level (AGL). However, both captive and free-ranging flocks exhibited behavioral responses to the rotary-wing UAS when flown within 30 m AGL. Behavioral responses of blackbirds to the rotary-wing UAS were more pronounced with lower altitude approaches. Our findings suggest that UAS have the potential to modify blackbird behavior in a way that may reduce sunflower crop depredation.
Bibliographical noteFunding Information:
The U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center (7438-0020-CA; QA#2348), the National Sunflower Association (16-P02), the State Board of Agricultural Research (16-P02), and North Dakota State University supported this project. Reference to trade names does not imply endorsement of commercial products or exclusion of similar products by the United States government. Research was approved by the North Dakota State University Institutional Animal Care and Use Committee (IACUC #A14068) and conducted under permits from the U.S. Fish and Wildlife Scientific Collecting Permit (#MB39327B-0), the North Dakota Game and Fish Department (#GNF03799268). North Dakota State University Research and Creative Activity approved all UAS flight plans. We would like to thank landowners and the North Dakota State University Agronomy Seed Farm for their cooperation and allowing us to fly over their land. We also thank our undergraduate employees for their assistance. Drs. Wendy Reed, Gary Clambey and three anonymous reviewers provided helpful comments for revising an earlier version of this manuscript.
- Frightening devices
- Human-wildlife conflict
- Unmanned aerial vehicles
- Wildlife damage