Avian responses to aircraft in an airport environment

Abstract

ABSTRACTUnderstanding how free‐ranging birds react to approaching aircraft can provide the foundation for predicting and mitigating risk of bird strikes. We characterized responses by avian species to aircraft (propeller‐driven, jet, rotorcraft) approach (taxi, takeoffs, landings) at Burke Lakefront Airport, Cleveland, Ohio, USA, from June 2015 through September 2016. Based on opportunistic observations from fixed points on the airfield, we quantified 208 bird‐aircraft interactions across 16 species. However, we focused analyses on 5 species with >10 bird‐aircraft interactions (n = 176): American kestrel (Falco sparvarious), European starling (Sturnus vulgaris), killdeer (Charadrius vociferous), mourning dove (Zenaida macroura), and red‐winged blackbird (Agelaius phoeniceus). We evaluated the common measure of perceived risk, flight‐initiation distance (FID), and the likelihood of response (i.e., a measureable FID), each relative to species, flock size, flock altitude, perch height, aircraft approach category, and airframe type. We also assessed effects of light, temperature, and wind speed. None of our predictors contributed to FID. Across the 5 species, birds exposed to direct aircraft approach were ≥2 times more likely to initiate escape as those approached tangentially. The larger mourning dove was, by a factor ≥2, more likely to initiate escape response. As flock size increased, birds were more likely to initiate escape response. Birds were >2 times more likely to initiate escape when approaches involved jets relative to propeller‐driven airframes. Because smaller species were less likely to initiate escape response, thereby enhancing the possibility of latent responses close to aircraft, we suggest that airport biologists should not disregard management to reduce strike hazards posed by smaller species. Further, bird habitat on airfields and fixtures that concentrate bird use in a direct line of aircraft approach will inherently increase the frequency of bird‐aircraft interactions. Finally, our findings on flock size and airframe type underscore the need for continued efforts to develop methods to enhance avian detection of and response to approaching aircraft. © 2019 The Wildlife Society.