Black bears are omnivores as well as opportunists. They will eat almost anything that they can find, but the majority of their diet consists of grasses, roots, berries, nuts and insects (particularly the larvae). In the fall, prior to going into hibernation, black bears enter a stage called “hyperphagia,” which literally means “excessive eating.” They forage practically non-stop — up to 20 hours a day, building up fat reserves for hibernation, increasing their body weight by 35% in some cases. Their daily food intake goes from 8,000 to 15-20,000 calories (that’s roughly equivalent to 70 McDonald’s cheeseburgers). Signs of their foraging for grubs and beetles, such as the excavated base of the snag in the photograph, can be found with relative ease at this time of year, if you live where there are black bears. If you do share their territory with them, be forewarned that they have excellent memories, especially for food sources. Be sure not to leave food scraps or pet food outside (my compost bin was destroyed last year but I have no solution for that particular problem), and if you really don’t want any ursine visitors, it’s best to not start feeding birds until most black bears have entered hibernation – late December would be safe most years.
I have to share this amazing opportunity to observe a black bear in her den at Lynn Rogers’ North American Bear Center in Ely, Minnesota. She is due to give birth any time now. http://www.bear.org/livecams/jewel-den-cam.php
Birds and mammals that rely on beechnuts as a staple of their diet include black bears, white-tailed deer, fishers, porcupines, wild turkeys, ruffed grouse, wood ducks, tufted titmice, and numerous small rodents, to name but a few. There is a good reason for this – beechnuts have about the same protein content as corn, but five times the fat content. Beechnuts also have nearly twice as much crude protein and twice the fat of white oak acorns and about the same fat content as red oak acorns. Given the number of husks and nuts that are on the forest floor this fall, it appears that this is a good year for beechnut mast, or seed production. Research has shown that high beechnut production in the fall is correlated with a high percentage of reproducing female black bears in the coming winter.