Date of this Version
From March 1996 to 31 December 1999, Wildlife Services (WS) personnel trapped and relocated 316 raptors from one of the nation's busiest airports: 147 American kestrels (Falco sparverius), 158 red-tailed hawks (Buteo jamaicensis), 5 rough-legged hawks (Buteo lagopus), 4 peregrine falcons (Falcoper-egrinus), 1 northern harrier (Circus cyaneus), and 1 eastern screech owl (Otus asio). On 1 January 1999, the Federal Aviation Administration sponsored a 2-year study, in conjunction with the National Wildlife Research Center and WS-Illinois, to evaluate the efficacy of raptor relocation at the airport. This study began in September 1999 and (1) monitors the post release activity of red-tailed hawks through the use of auxiliary markers (color legbands) and VHF and satellite telemetry technologies, (2) calculates the return rate with respect to relocation direction and distance, and (3) determines the overall efficacy of raptor relocation as a method to reduce raptor strikes. Twelve adult (after hatch year) red-tailed hawks were fitted with satellite/VHF transmitters and another 12 were fitted with VHF transmitters. They were captured during June and July 2000 and translocated 150 miles south-southwest of ORD. Preliminary analysis of post-release movements indicated that translocated red-tails remained at the release sight for approximately 4 days before making significantly northern movements. One hawk remained at the release site for greater than 2 months before heading in a predominately western direction. Eight of the 24 red-tails returned to or near the airfield. Four were resighted within the A.0.A.-1 was within 13 days of release—and 4 others returned to within 2 miles of the airport-1 was 2 days after release. However, of the 4 hawks that returned to the A.O.A., only 2 were consistently observed within the A.O.A through 4 October 2000.