Bird Control Units - when a bird hits an aircraft this is known as a bird strike. Bird strikes are the single greatest cause of accidents sustained by military aircraft and tragically the loss of human life or serious injury to aircrew.   As most birds fly below 1,000 feet and the majority of them below 500 feet above ground level, so it is the aircraft flying at low level, taking off and landing, that is the most vulnerable.  In 1965 the Fleet Air Arm implemented a bird control programme at its air stations, and in 1972 the Bird Control Unit moved to its present location at RNAS Yeovilton and began operating using similar methods and in 1975 the operation was extended to include RNAS Culdrose.    The Fleet Air Arm has used falcons as a method of combating bird strikes since 1965.