Yet there never has been a demographic study of the Glacier National Park grizzly bear population and no data exist on population size, status, or trend. The grizzly bear population in the Northern Continental Divide Ecosystem can not be delisted without reliable information on ecosystem-wide population trends, of which the bears in Glacier National Park are a critical component. Until now, statistically rigorous grizzly population studies in forested habitat could only be accomplished with radio telemetry. Traditional studies entail intensive trapping with baiting, drugging, collaring, ear tagging, and frequent aerial radio tracking. Large numbers of grizzly bears are handled.
Trapping requires closure of portions of the park to visitors.
Cost considerations, along with ethical and social concerns, prohibit their application to most grizzly bear populations. A pilot survey in Glacier National Park demonstrated the feasibility of collecting adequate sample sizes of bear sign to obtain minimum counts and to reveal population declines without handling bears or conducting aerial overflights. Since 1984, bear sign has been collected each fall from 240 km of Glacier National Park trails. Approximately 200 hair and 100 scat samples were found per year. Based on within and between year variation in the amount of sign found, simulation modeling demonstrated that a biologically significant decline in sign could be detected with this survey design if bear species could be identified from scats.