This is the first report of Clark's Nutcrackers (Nucifraga columbiana) harvesting seeds from the cones of sugar pine (Pinus lambertiana), based on observations over several years in Crater Lake National Park, Oregon. The harvesting period in late September corresponded to peak cone-opening dates. Nutcrackers placed harvested seeds in their throat pouches, a behavior associated with seed caching.
Murray, Michael P. and Tomback, Diana F.
"Clark's Nutcrackers harvest sugar pine seeds from cones,"
Western North American Naturalist: Vol. 70
, Article 14.
Available at: http://scholarsarchive.byu.edu/wnan/vol70/iss3/14