I performed a brief comparative study of foraging versus construction uses of different species of trees and shrubbery found upon beaver lodges in the Boundary Waters Conservation Area. I hypothesized that beavers prefer to use certain species of trees and shrubbery for constructive purposes rather than foraging. Results from the study show that aspen constituted 35%, alder 30%, and birch 25% of all pieces of trees and shrubbery sampled from lodges. Twelve other species made up 10% of the pieces found on lodges. Of uneaten samples, alder makes up the highest number (99 pieces), birch (19 pieces) and the remaining 32 uneaten pieces are comprised of 12 other species excluding aspen. This information suggests aspen is always eaten before becoming part of the lodge. In addition, birch is eaten part of the time, and alder (as well as all other unpeeled species found) are never eaten before being used for lodge construction. These results add both controversy and questions to those studies done previously on the foraging habits of Castor canadensis (Canadian Beaver).
Eric Byrne, ’01 Cedar Rapids, IA
Sponsor: Martha Condon