Bird strikes are a significant threat to flight safety, and have caused a number of accidents with human casualties. The number of major accidents involving civil aircraft is quite low and it has been estimated that there is only about 1 accident resulting in human death in one billion (109) flying hours. The majority of bird strikes (65%) cause little damage to the aircraft; however the collision is usually fatal to the bird(s) involved.
Most accidents occur when there is a collision involving a bird (or birds) and the windscreen or a bird (or birds) is sucked into the engines of mechanical aircraft. These cause annual damages that have been estimated at $400 million within the United States of America alone and up to $1.2 billion to commercial aircraft worldwide. In addition to property damage, collisions between man-made structures and conveyances and birds is a contributing factor, among many others, to the worldwide decline of many avian species.
The International Civil Aviation Organization (ICAO) reported 65,139 bird strikes for 2011–14, and the Federal Aviation Authority counted 177,269 wildlife strike reports on civil aircraft between 1990 and 2015, growing 38% in 7 years from 2009 to 2015. Birds accounted for 97%.