The monograph is not only of special, but also of general biological interest. Two volumes of this publication cover the biology and status of 312 species of birds found in the Leningrad region. and adjacent areas. Particular attention is paid to the nesting life, distribution and history of resettlement, directions of changes in the number, behavior and attitude of birds to humans. The changes that have occurred in avifauna over the past century are analyzed. An annotated list of rare birds in need of special protection is provided.