The purpose of this research project was to develop a radar technique to detect the presence of flying birds potentially hazardous to aircraft near airport runways; to distinguish them from other radar targets; to estimate the size and number of birds in order to assess the hazard. The motions of a bird in flight are characterized by a distinctive velocity spectrum that can be detected by radar. These 'aural signatures' were identified by Doppler technique and verified by visual sightings. This report provides a description of the analysis techniques, compares range-gated to nonrange-gated systems and also conventional and Doppler radars. A discussion concerning modification of a typical system to a Doppler system is included. A method of determining the actual number of birds in the target volume is discussed. The report also includes a scene-by-scene description of a film presentation made to more fully quantify the Doppler technique. (Author).

A hearing about the collision of an airliner with a flock of birds which forced the pilot, Chesley Sullenberger, to land the crippled aircraft on the Hudson River, which he did successfully.