Abstract

The rising number of aircraft collisions with birds requires the development of appropriate mitigation measures to control their populations in the vicinity of airports. The black vulture (Coragyps atratus; vultures) is considered one of the most dangerous species for aviation in Brazil. To better understand the spatial distribution patterns of flying vultures and the risks they may pose to aviation, we studied natural and anthropogenic superficial factors and then numerically estimated and mapped the risk of collision with birds over the Airport Safety Area (ASA) for the Amarais Airport and Presidente Prudente Airport in the southeast part of Brazil. To conduct our research, we surveyed soaring black vultures monthly between September 2012 and August 2013 from 26 points within 20-km ASA zones. We obtained the environmental parameters (i.e., relief, surface temperature, surface covering type, and anthropogenic pressure) from satellite imagery and georeferenced them with our vulture survey. The tabulated data were examined using Spearman’s rank correlation and principal component analysis to determine if any the relationships existed between vulture flight patterns and ASA environmental characteristics. We found that the contrast in surface temperatures correlated well with the intensity of vulture soaring flights. Vultures tend to soar using the strongest thermals in their surroundings. Relief parameters, including altitude above sea level, slope exposure, and inclination, were not related with the vulture soaring activity. Water bodies and roadways were the most attractive landscapes for soaring vultures. We recorded the least number of soaring vultures over the uninterrupted urbanized lands. However, the scattered enclaves of urban settlement surrounded by natural and rural landscapes were selected by soaring birds. To mitigate the bird strike risk in ASA zones, we propose that managers should plot the objects generating thermals that attract vultures on risk assessment maps and reroute aviation to avoid them.