The Atlas-determinant sets out the methodology for determining the 25 species of birds most dangerous for aviation by their macro-and microstructural fragments, indicates the ranges, describes their appearance and provides a complete list of aircraft-hazardous birds of the USSR fauna. Particular attention is paid to the diagnosis of feather fragments, which are most often found as bird remains in collisions with airplanes and helicopters. Atlas-determinant is intended for members of commissions for investigation of flight accidents and prerequisites for them due to collisions of aircraft with birds, aviation ornithologists, meteorological service specialists, chairmen of non-standard ornithological commissions of aviation units and personnel of various services involved in ornithological support of flights.