TO: Participants receiving the questionnaire concerning grizzly bear sightings during 1983-1987

Authors(s): L. L. McDonald

Publication:

Publisher: University of Wyoming College of Commerce and Industry Department of Statistics and Statistical Consulting Center

Publication Date: 0000-00-00

Type: letter

Location: Laramie WY

Abstract: The first year of our study for grizzly bear sightings in Yellowstone National Park and surrounding areas has been completed. We thank you for your participation. As you will recall, individuals throughout this region who were likely to know about grizzly bears were sent a questionnaire and asked to indicate when and where they had sighted grizzly bears. We were able to investigate (1) the relationship of reported grizzly bear sightings to sightings verified by government management agencies, (2) trends in reported grizzly bear sightings for the years 1983 through 1987, and (3) the spatial distribution of grizzly bear sightings. A map displaying all reported grizzly bear sightings is enclosed and a summary of results are presented below. A copy of the entire report can be obtained from the above address for a fee of $20.00 to cover duplicating and mailing costs. 1. Most of the sightings indicated on the returned questionnaires agree closely with the distribution verified by government management agencies. However, there are four areas outlined on the map which have sightings outside the distribution indicated by management agencies. The four areas are: (1) the eastern region of the Beaverhead National Forest that is south of Ennis, Montana and east of the Madison River, (2) the northern portion of the Gallatin National Forest that lies between the Yellowstone and Gallatin Rivers, (3) portions of the Gallatin and Custer National Forests that are north of Yellowstone National Park and south of the Yellowstone River, and (4) a region north of Dubois, Wyoming. 2. In 1986, respondents reported more grizzly bear sightings than in 1987. These results agree with the "common knowledge" that 1986 was an exceptionally good year to observe grizzly bears. 3. Reported sightings indicate that individual grizzly bears are more widely distributed than are sows and cubs. Also, between 20% to 25% of the reported sightings of grizzly bear sows and cubs were outside regions indicated by management agencies. 4. Respondents estimated the number of weeks that they spent in the backcountry of the study area for the years 1983 through 1987. Using these estimates, grizzly bear sightings per man month were calculated. The number of grizzly bear sightings per man month (of time spent in the backcountry of the study area) increased from 0.104 bears per man month in 1983 to 0.279 bears per man month in 1987. It is important to note that there are numerous factors other than an actual increase in the grizzly bear population size that could explain the observed large increase in sightings per man month. These include: (1) increased awareness of individuals to "look out for grizzly bears," (2) changes in weather, habitat, or food availability that could change the lkelihood of a grizzly bear sighting, and (3) potential biases in the survey since respondents were requested to recall the past. In particular, we believe that there may be a tendency for individuals to overestimate the amount of time that they spent in the field during the years 1983 through 1985. Conjectures concerning changes in the grizzly bear population size are premature at this time. 5. Considering the respondents who expressed an opinion, 66% expressed the opinion that the grizzly bear population is increasing. 6. We observed an expansion in the range of grizzly bear sightings. When comparing the earlier years, 1983 and 1984 to the most recent years, 1985 through 1987, a shift of signtings to the south, southeast, and north of Yellowstone National Park was reported. Information obtained from this survey is useful in understanding changes in the distribution and range of grizzly bears. With your help, we plan to continue this study for two more years. This year we will be requesting only 1988 sightings. If you receive a questionnaire, please take a few minutes to complete and return it. We appreciate your help.

Keywords: animal, mammal, bear, Ursidae, grizzly bear, Ursus arctos horribilis, Yellowstone National Park, Greater Yellowstone Ecosystem, population, mortality, habitat, food, forage