Bird Strike Committee Proceedings


Date of this Version

August 2005


In June 2001 we initiated a Raptor Strike Avoidance Program to monitor raptor activity and develop a biologically-based approach to reduce raptor densities at Seattle-Tacoma International Airport (SEA), King County, WA. Weekly surveys established the species, sighting frequencies, and distributions of raptors. Red-tailed Hawks (RTHAs), our most common raptor, occur as both resident and migrant/wintering hawks. We attached colored leg bands, backpack radio-transmitters and wing-tags to 8 of 12 resident RTHAs to identify individuals, locate nests and to assist in defining territories. These adult RTHAs were released onsite with the expectation that they would act as “sentinel” hawks by driving the young and inexperienced birds away from the airport. Numerous observations of resident and non-resident RTH interactions have supported the decision to mark/release territorial resident RTHAs back at SEA. Migrating and wintering RTHAs, and other frequently occurring raptors such as American Kestrels (AMKEs) and Cooper’s Hawks (COHAs), were captured at SEA and released at an agricultural site with higher prey abundance 70 miles to the north. To alleviate the problem of young RTHAs being more commonly struck by aircraft, we relocated three-week old RTHAs from their nests and hacked (raised/released) them 70 miles away at the same release site. As of 14 June 2005, we have captured 110 raptors, including 70 RTHAs, 20 AMKEs, 14 COHAs, 2 Sharp-shinned Hawks (SSHAs), 1 Peregrine Falcon (PEFA) and 3 Great Horned Owls (GHOWs). No relocated birds are known to have returned from the “superior” habitat. This paper summarizes our activities, presents a partial list of our results, and discusses techniques now under development.