Birds don't hit just buildings.
http://www.aphis.usda.gov/ws/nwrc/field/sandusky/index.html - the site of the National Wildlife Research Station in Sandusky, Ohio.
The primary focus of research at the NWRC Sandusky, OH, field station concerns wildlife hazards to aircraft. Commercial jet aircraft traffic has shown a dramatic increase. Wildlife on and near airports create a hazard to operating aircraft. Wildlife strikes can cause severe damage to aircraft, human injuries, and loss of life. Between 1990 and 2003, 52,000 wildlife strikes were reported to the U.S. Federal Aviation Administration (FAA); 10% had an adverse effect on the aircraft or flight operation. The estimated cost of wildlife strikes to U.S. civil aviation 1990-2003 was almost $500 million per year. Internationally, the commercial aviation industry incurs a loss of over $1.2 billion annually from wildlife strikes with aircraft. U.S. military losses are estimated to be over $100 million annually. As one dramatic example, the U.S. Air Force lost 24 airmen and a $190 million AWACS plane in 1995 after the aircraft hit geese on take-off at Elmendorf Air Force Base, AL.