The Columbian ground squirrel (Spermophilus columbianus), Richardson ground squirrel (Spermophilus richardsoni), and blacktail prairie dog (Cynomys ludovicianus) cause millions of dollars of loss to Montana agriculture each year. Montana's ground squirrel and prairie dog control programs are based upon local organization and operation with technical assistance being provided by the Montana Department of Livestock Vertebrate Pest Control Bureau. The results of field research programs using zinc phosphide, Compound 1080 and strychnine grain baits to control these species are reported.

Some complexities and limitations of using carcass residue data to determine secondary hazard to nontarget species are discussed. The roles of chemical and toxicological properties of the rodenticide such as metabolism, excretion, organs of retention, site of absorbtion and latent period in secondary hazard are reviewed and examples given. The possible effects of bait composition and application methods, the behavioral response of the nontarget species, and local environmental factors upon secondary hazard are outlined.

An attempt was made to identify the olfactory cues produced by Douglas-fir seeds which attract deer mice (Peromyscus maniculatus) to the seeds. The olfactometers used are described, and the merits of different statistical analyses of the data are discussed. The odors produced by whole Douglas-fir seed and by the endosperm were preferred among the fractions tested to date. Deer mice were repelled by Douglas-fir turpentine, cedar oil, and, to a lesser degree, one extract.