Effectiveness of two anticoagulant rodenticides (chlorophacinone and bromadiolone) for Columbian ground squirrel (Spermophilus columbianus) control in eastern Washington

Over the years a number of techniques for control of ground squirrels have been developed and used with varying degrees of success. Some have used bait stations, others the broadcast application of chopped vegetable matter and cereal grains. No data were found on the broadcast application of pelletized materials. Two toxicants, chlorophacinone and bromadiolone, were mechanically broadcast over six plots during the summer of 1983. Results were good (70–80% mortality) with the mid-season application, and excellent (100%) with the late-season treatment. Problems of migration compounded part of the study which points out the need for complete coverage to achieve control.