The bird collection was initiated by David Hurst Thomas in the late 1960s while conducting archaeological research in Nevada. Since that time, the collection increased in an ad-hoc manner by graduate students and other researchers preparing specimens (e.g., Tim Carpenter, Michael Delacorte, Anastasia Leigh, Dwight Simons, Peter Schulz). After 2001, Christyann Darwent increased the number of California species and also added a number of birds that breed in the Arctic. A total of 147 specimens, primarily from California and Nevada, represent 70 different species.