A Study Of The Beaver In The Yancey Region Of Yellowstone National Park PDF Download

"The number of active beaver (Castor canadensis) colonies in Yellowstone National Park was determined by aerial survey in late October and early November 1996. This was the first near-complete autumn aerial count of beavers in park history. Flying time for the survey was 14.9 house, plus 4 hours ferry time from Bozeman, Montana, for a total of 18.9 hours. Total number of beaver colonies with food caches was 49; three other sites had beaver sign (beaver dam or cutting) indicating that beavers were probably present, but no lodge or food cache was sighted. Ninety percent of the park's beavers were located in three areas: 1) the Yellowstone River southeast of Yellowstone Lake, 2) the Beechler area, and 3) creeks and rivers in the northwest corner of the park which included the Madison and Gallatin rivers, and Cougar, Campanula, and Gneiss creeks. There was only one beaver colony on Yellowstone's Northern Range. All colonies were associated with willow (Salix spp.)."--Page 1.