Bird Strike Committee Proceedings


Date of this Version

August 2000


Wildlife Services’ (WS) activities at O’Hare International Airport (ORD), 1997-1999, significantly reduced the annual number of wildlife strikes reported for ORD. The average annual number of reported strikes decreased from 104.2 (1992-1996) to 49 (1997-1999). However, the number of strikes involving red-tailed hawks (RTHA, Buteo jamaicensis) and American kestrels (AMKE, Falco sparverius) did not change (14.6 per year). On 1 January 1999, the Federal Aviation Administration sponsored a two-year study, in conjunction with the National Wildlife Research Center and WS-Illinois, to evaluate the efficacy of raptor relocation at ORD. All relocated RTHA were to be fitted with both a United States Geological Service band and an alpha-alpha colorband and then released roughly 64 km, in three different headings (south, west, and northwest), from ORD. In June 2000, 12 resident RTHA were fitted with satellite transmitters and an additional 12 fitted with vhf transmitters. These birds were released 240 km southwest of ORD. The return rate of RTHA based on recapture and recovery data is 8.7% (13 March 1996 – 15 March 2000, n=184 with 16 recoveries). The return rate based on resight and recapture of color-banded RTHA is 13.04% (2 December 1999 – 15 March 2000, n=46 with 6 resights). The use of vhf and satellite transmitters will greatly enhance our ability to track relocated raptors, identify post-release status, more accurately determine the return rate, and possibly identify habitat use by that non-returning RTHA to aid in site selection for future relocations.