Before applications were made of a commercial formulation of fenuron (3, phenyl-1, 1-dimethylurea) to control vegetation on the Pyatts Stripmine Research Area, Perry County, Illinois, tests were conducted to determine its toxicity to bobwhite quail (Colinus virginianus). This herbicide, manufactured by DuPont under the trade name "Dybar," was supplied by the Industrial Chemicals Supply Company, Springfield, Illinois. Pellets of fenuron used in the experiments were randomly selected from a 50-lb bag of commercial grade. Individual pellets were cylindrical, averaging 3 mm in diameter, 4 mm in length, and 29.33 mg in weight. The active ingredient, fenuron, composed 25 per cent of the compound; the remainder was an inert clay. The pellets were designed to disintegrate in 3 to 4 minutes when in contact with lukewarm water. "Dybar" becomes effective when the fenuron compound has penetrated the soil to the root zones. The soil may be toxic to further plant establishment and growth for several years.