Predator Study Will Help Elk Management
Idaho Department of Fish and Game
May 3, 2001
The elk population in the Upper Clearwater Basin has declined dramatically over the last decade and the Idaho Department of Fish and Game has begun a study to determine if predators are a major part of the problem. The agency will work with hunters and outfitters to reduce predator populations in one of four study treatment areas and compare calf survival there with survival in other areas.
According to wildlife biologist Pete Zager, many factors are involved. It is apparent that habitat quality has declined, and that habitat quality, the physical condition of the cows, pregnancy rates, and calf growth rates play important roles in elk production. It also appears that predator populations have increased. The goal is to develop a better understanding of the role these factors play, and how they might interact with predation. Since 1997, predation has claimed 30-80 percent of radio-collared elk calves on Fish and Game study areas. Some have suggested that predator control alone can reverse the elk population decline. To test whether this hypothesis is correct, Fish and Game proposes to significantly increase predator harvest in a small experimental treatment area. Fish and Game will compare elk population recovery in that area with other areas where alternate actions will be evaluated.
The manipulation of black bear populations in a portion of game management units 12 and 15 is designed to improve understanding of the relative role of predation. The Unit 12 treatment area represents less than two percent of the Clearwater Region. Biologists estimate that there is about one bear per square mile in this study area where the research goal is to reduce the black bear population by half. Within the Unit 15 treatment area, the black bear harvest season has been closed and the population allowed to increase. This will provide a meaningful contrast with the Unit 12 treatment. The findings will be compared with two control areas, where elk and bear management will not be altered. In all four areas, Fish and Game will continue to measure elk calf survival, cow pregnancy rates and physical condition, and other variables.
Currently, Fish and Game is working with hunters and outfitters to temporarily reduce the black bear population in the Unit 12 treatment area using well-established and legal hunting techniques. Outfitters operating within the treatment area have agreed to intensify harvest efforts. Fish and Game has purchased bags of dog food to be used for bait in the area. Although outfitters are buying most of the bait, the purchases by Fish and Game will help offset increased costs to outfitters who help out with this study. The effort was begun with the opening of this spring's bear hunting season so that the population would be reduced when elk begin calving later in the year. Fish and Game understands the public concern about the effort to increase harvest as part of the study. It is a short-term event in a small study area, and is not intended to become a regular management practice. This project will provide a better understanding of the relative role predation, habitat quality and structure, elk physical condition and pregnancy rates, elk densities and other factors play in elk population dynamics. The results will help managers work toward a balance between elk, bears, and lions to meet wildlife objectives. IDFG