When black bears first emerge from hibernation, they survive mainly on emerging green vegetation in wetlands. As the season progresses, there are more and more food options to choose from, including a favorite – the corm, or underground bulb-like storage structure, of Jack-in-the-Pulpit. Even though they are large, somewhat lumbering creatures, black bears dig up and remove these corms as if they had a tiny tool designed just for this purpose. They barely disturb the earth, leaving only very small holes as evidence of their presence. A friend of mine witnessed this just outside his window one spring day, and could not believe the delicacy with which the bear extracted these morsels of food from the ground. Apparently the calcium oxalate crystals in Jack-in-the-Pulpit that cause the burning sensation in human mouths doesn’t affect bears, at least not enough to protect the plant.
Recent discovery of black bear tracks and scat confirm that hibernation has come to an end, at least for some bears. During the winter black bears lose an average of 23% of their body weight. Because there is a scarcity of food when they emerge from their dens, black bears continue to subsist off the fat that they put on last fall, and thus continue to lose weight. The diet of black bears is high in carbohydrates and low in proteins and fats. When hibernation is over, they head for any available succulents and protein-rich food, including bird feeders.
I can’t let another minute pass without bringing a website to my readers’ attention, as activity has really picked up recently. The live-cam installed inside a bear den in Ely, Minnesota at the North American Bear Center captures the sounds and movements of a mother bear and her two six-week old cubs 24 hours a day. Everything from the mother’s birth to the fall and rescue of a cub has been recorded. Enjoy part of your snowy (or not) Sunday by taking a look at this ursine family. You may have to have considerable patience before seeing a cub, but it will be worth it, and you’ll hear them night and day! It will be obvious to you that female black bears with newborn cubs do not have the luxury to go into as deep a hibernation as their mates, who are blissfully asleep in their own den. Go to http://www.bear.org/website/live-cameras/live-cameras/lilys-den-cam.html and click on “live stream” in the upper right hand corner of the picture of the bear to view live coverage. You can also see tapes of past activity, both here and on “Lily the Black Bear’s” Facebook page.
If you look up occasionally when you are in a beech-maple forest, you may observe a sizeable cluster of twigs and branches fairly high up in an American beech tree. This “nest” of twigs is usually bigger than any squirrel’s nest and not cup-shaped like a hawk or owl’s nest. In fact, it isn’t a nest at all – it is a sign that a black bear has been sitting, usually in the crotch of the tree, pulling, biting and breaking off branches primarily in order to eat nuts (leaves, buds and catkins are also consumed). When the bear is finished eating what it desires, it discards the branch into a pile. Although known as a bear “nest,” this pile of branches is not a resting spot for bears. If you’re not convinced that a pile of twigs you find was made by a bear, and if it’s in a beech tree, try looking for claw marks on the smooth bark. If it’s a bear “nest,” you’ll most likely find some! (Discovery by Alfred Balch)
This may well be the last month until spring in which signs of active black bears can be found – cold temperatures and a poor beechnut and acorn crop may hasten their retreat into their dens. A black bear’s track is fairly distinctive, if only due to its size: 3 ½”- 6” wide by 4”-9” long. Black bears are flat-footed, or plantigrades, and thus you see more than just the toe imprints in a track; the heel pads of the hind feet are larger than those of the front feet. Black bears have five toes on each foot. The smallest, outside toe often doesn’t register. Long, curved nails on a black bear’s front feet are used for marking trees and climbing; the hind feet nails are much shorter.
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.
Black bears are known for denning in a variety of locations, including under logs and stumps, under the branches of a fallen tree and inside caves and hollow trees. Occasionally they choose a site where they are fully exposed, such dense thickets. This photograph of an abandoned den is just that — a depression in the middle of a stand of almost impenetrable red spruces which bears have lined with broken spruce boughs. The imprint of two small bears (likely two year olds) in the needles, plus other nearby signs confirm that this den was inhabited fairly recently. With the mild winter we’re having and the abundance of fruits and nuts this past fall, the hibernation habits of bears may well have been altered – I know of tracks that were spotted in January as well as this month — one typically wouldn’t expect to find bears emerging from their dens much before late March or early April. (Notice bark is missing on some of the nearby spruce trunks from bears biting and tearing it.)