Developing Strategies for Long-Term Removal of Raptors from Airports in California

Airports in southern California have experienced a number of damaging bird strikes associated with raptors during the last 10 years, including two substantially damaging strikes involving red-tailed hawks. Southern California airfield habitats attract a large variety of small birds and rodents, especially California ground squirrels and pocket gophers, which attract red-tailed hawks and other predators into aircraft movement areas. Effective, publically acceptable methods to reduce prey populations and/or reduce raptor use of airport habitats are needed. Over a 14-month period during 2006-2007, body grip traps and gas cartridges were used to remove 927 California ground squirrels from one airfield. Monthly raptor observations were directly correlated with the reduction in ground squirrels. Red-tailed hawk observations were reduced by 47% and ground squirrels capture rates were reduced by 98% after ground squirrel management efforts were undertaken. Swedish goshawk traps (SGT) and Australian crow traps (ACT) positioned in areas utilized by hunting raptors (e.g., between the runways) were used to live-capture and relocate a variety of raptors from 3 southern California airports (from August 2006 through April 2008), consisting of: (Airport #1) 2 BAOW, 1 GHOW, and 16 RTHA; (Airport #2) 1 AMKE, 1 COHA, and 18 RTHA, and; (Airport #3) 9 RTHA and 9 COHA. Effective use of SGT required modifications to trap location and use of bait and decoys (e.g., a live rock pigeon secured below the perch mechanism). The ACT required the action of Airfield Operations to close the trap door once a raptor was observed inside of the trap. Modifications to ACTs increased trapping efficiency. Prey reduction and raptor trapping methods (SGT and ACT) are effective wildlife mitigation tools acceptable to the public for the live-capture and relocation of raptors, allowing for reduced risk of raptor-aircraft collisions at airports in southern California and elsewhere