We documented black bears (Ursus americanus) consuming the seeds of Jeffrey pine (Pinus jeffreyi) in the eastern Sierra Nevada from late August through September. Shells of pine seeds were the exclusive item in 20 of 27 scat samples collected in September and October and comprised >90% of the remaining 7 samples. Bears obtain seeds of Jeffrey pines by climbing trees, removing ripe, unopened cones from branches, dismantling cones on the ground, and consuming the seeds. Cone harvesting by bears can cause substantial damage to cone-bearing trees and might result in high predispersal mortality of seeds. In other regions, the use of pine seeds by bears has been associated with whitebark pines (P. albicaulis) from which bears obtain seeds by exploiting the cone-storing activities of squirrels. Despite the lack of an apparent pine-squirrel-bear interaction, harvesting unopened cones might be a common foraging strategy used by black bears to obtain seeds of Jeffrey pines in the Sierra Nevada.
Kuhn, Kellie M. and Vander Wall, Stephen B.
"Black bears (Ursus americanus) harvest Jeffrey pine (Pinus jeffreyi) seeds from tree canopies,"
Western North American Naturalist: Vol. 67
, Article 7.
Available at: http://scholarsarchive.byu.edu/wnan/vol67/iss3/7