The United States Geological Survey (USGS) Arid Lands Field Station has curatorial responsibility for more than 48,000 Federal specimens of vertebrates that are housed in the Museum of Southwestern Biology (MSB) at the University of New Mexico. The collection originally was established to support food habits studies in the 1920s by the Bureau of Biological Survey and now serves as a repository for specimens taken in support of Federal research in the West. Included are holdings of fishes, amphibians, reptiles, birds, and mammals, and more than 90% of the collection postdates 1970. Original field notes, collectors' catalogs, and frozen tissues supplement the collection; all specimen data have been computerized. The bird and mammal records can be queried via Arctos, a searchable online database.