Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solarpowered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006-30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than did turkey vultures in all seasons except summer when altitudinal distributions (above ground level) did not differ. Although we recorded maximum altitudes of 1,578 m for black vultures and 1,378 for turkey vultures, most flights were low altitude. A matrix of vulture flight altitude versus time of day revealed that >60% of vulture flight activity occurred from 4 hr to 9 hr after sunrise at altitudes below 200 m. Continuation of aggressive harassment coupled with flexible training schedules to avoid times and altitudes of high vulture activity will decrease hazards to aircraft posed by these birds.

In the United States, black vulture (Coragyps atratus) and turkey vulture (Cathartes aura) pose significant birdstrike risks to aircraft. Understanding flight behaviors of vultures in and around military and civilian airfields is necessary to alleviate these risks. Using satellite telemetry data collected from 11 black vultures and 7 turkey vultures equipped with Global Positioning System backpack harness technology, we collected data on location and altitude near the Marine Corps Air Station (MCAS) in Beaufort, South Carolina from September 2006 to September 2008. We used military aircraft flight landing patterns to visualize a new concept, a flight altitude cone of depression (FACOD), which models a three-dimensional flight pattern over the airfield. We then identified areas in and around MCAS where vulture flight paths penetrated the FACOD and locations of vultures were proximate to flight approach routes that posed potential risk to aircraft for a birdstrike. Combining altitude of in-flight locations of vultures or other species with three-dimensional flight patterns of aircraft provides a novel method for managers of military and domestic airfields to assess birdstrike risk and to focus corrective actions.