George Matschke worked as researcher at the Wildlife Research Center from 1968 until his retirement in 1999. This collection contains records (dated 1955-1999) that were collected by Matschke. Included are administrative records, Bird Unit work reports, research records mostly pertaining to rodent control, as well as numerous images of research projects conducted by Matschke and other scientists at the Center.

Paul L. Hegdal worked as a wildlife biologist at the Denver Wildlife Research Center from the 1959 to 1991. This group of records contains materials related to studies on hazards to nontarget wildlife associated with the use of rodenticides, rodent resistant cable materials, and rodent problems in Latin America.