The Effects of Herbicidal Spraying Upon a North Central Utah Blue Grouse Population

The effects of herbicidal spraying upon a North Central Utah blue grouse population were studied. Baseline data were obtained in 1970 and 1971 prior to the spraying on June 2, 1972. The spraying was done to control wyethia (Wyethia amplexicaulis) and black sage (Artimesia nova) which covered 48 percent and 20 percent of the study area respectively. No differences in blue grouse numbers occurred following spraying with 17 to 20 broods using the area in 1972 compared to 18 to 20 broods in 1971. Total population of blue grouse each year was between 90 and 104 birds. Distribution of blue grouse changed, with the birds using areas with trees and shrubs following spraying rather than open areas that were sprayed. There was significantly more black sage on the control area than the spray area. These differences began before spraying, however, and cannot be attributed solely to the spray. No differences occurred in insect numbers or songbird use of the spray and control area