The Cooper Ornithological Society Records, 1874-1993, document the organization's history from its origins as a small association of naturalists to its current status as a renowned scientific society with extensive international membership. The bulk of the collection consists of correspondence and administrative records produced by the Board of Directors and COS Officers. Also prevalent are committee minutes, annual meeting materials, and individual member correspondence and field notes. Materials relating to the official publications of the society, including The Condor and Studies in Avian Biology, are also included.

The Cooper Ornithological Club (COC), the forerunner of the present Cooper Ornithological Society, was formed on June 22, 1893 in San Jose by four active birders and oologists in order to provide a forum in which to study and discuss birds with like-minded, well-informed enthusiasts. In December 1934 the Club became incorporated, and in May 1952, the Club changed its name to the Cooper Ornithological Society, with the principal intent of better conveying the club's academic and scientific orientation. The Society currently numbers over 3000 professional and amateur ornithologists from around the world. The primary goal of the Society, as expressed through its meetings, sponsorship of symposia, and publications, is to advance the scientific study of birds and their habitats, and support their conservation.

Number of containers: 13 cartons, 1 oversize box, and 7 volumes. Linear feet: 17.5 linear ft.

Copyright has not been assigned to The Bancroft Library. All requests for permission to publish or quote from manuscripts must be submitted in writing to the Head of Public Services. Permission for publication is given on behalf of The Bancroft Library as the owner of the physical items and is not intended to include or imply permission of the copyright holder, which must also be obtained by the reader.

Collection is open for research.