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Greater Yellowstone Ecosystem Report

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Grizzly bears have been moving slowly southward in the Tetons and increasing their abundance over the last 20 years. Their distribution is now expanding into areas previously occupied by black bears only that are heavily developed and receive proportionately more recreational use. At the same time, white pine blister rust and other human­caused factors may reduce bear food abundance in the near future. Grand Teton National Park is now positioned for an unprecedented interplay of bears, declining bear food sources, and humans in a relatively small temporal and spatial scale. In a new study designed to provide information critical to future black and grizzly bear conservation in this area, 6 spread spectrum technology (SST) GPS radio collars were deployed on black bears in the southern end of Grand Teton National Park in 2005. SST collars allow interrogation of the data in the GPS unit on a regular basis. GPS units were programmed to record positions every 90 to 190 minutes, and data were downloaded aerially on a weekly basis. Four female bears, two with cubs of the year, an adult male, and a subadult male provided the bulk of approximately 2700 positions obtained in 2005, about 1560 of which were visted for detailed site analysis. Sites visited were based on a randomly selected 24 hour period for each bear each week, and all sites were visited within a week of the location's recording. Efforts in 2006 will focus more intensively on site visits and associated data collection and analyses.