Collective effect of landfills and landscape composition on bird–aircraft collisions

Ninety-three percent of all reported bird strikes occur below 1,067 m, which based on the typical approach and departure angles of aircraft is within 8–13 km of an airport. Concomitantly, the Federal Aviation Administration and the International Civil Aviation Organization recommend that any feature that would attract hazardous wildlife to the approach and departure airspace be restricted. Thus, preventing the establishment of wildlife attractants, such as municipal solid waste landfills (MSWLFs) within 8 km or 13 km extents (U.S. and international recommendations, respectively) of airports, has been recommended to mitigate the risk of bird–aircraft collisions (strikes). However, robust evidence linking wildlife attractants at these spatial scales to an increase in strikes is lacking. We investigated the effect of densities of MSWLFs and construction and demolition (C&D) landfills, landscape diversity, and human population density on the adverse effect (AE; strikes that caused damage or had a negative effect on flight) bird strike rate involving species broadly associated with MSWLFs. We predicted that airports surrounded by a high density of MSWLFs, high human population densities, and high landscape diversity would increase the AE strike rate. We evaluated our predictions via generalized linear mixed models with bird strike data from 2009 through 2017 at 111 Part 139 airports. Only U.S. airports were used because of high wildlife strike reporting rates. Part 139 certificated airports are those that facilitate air carriers with >30 seats for passengers and crew. Our average model included density of MSWLFs and C&D landfills for both the 8and 13-km extent from the airports. We found no significant contribution by any variable to the AE strike rate variance. Our results indicated that the effects of landfills on AE strike rates are inconclusive. Possible explanations for our findings include the influence of unmeasured landscape features and lack of fine-scale data on bird habitat use at landfill facilities. Future research should investigate bird 3-dimensional space use in addition to bird and habitat survey techniques.