Nature Notes

Now is a good time for an update on black bears, but why? One reason is that Massachusetts’ black bear population, at 4,500-5,000 bears, is growing and expanding eastward – into our area. Another big reason is that now, in spring, call it March-April, black bears (Ursus americanus) are coming out of hibernation. They’ll be out and about, though not necessarily near humans.

Meghan Crawford, community engagement biologist with Mass Division of Fisheries and Wildlife (MassWildlife), noted in a bear talk for the Westborough Community Land Trust (WCLT) that hungry black bears head to wetlands in spring. For what? Skunk cabbage (Symplocarpus foetidus). It’s one of spring’s first wild plants to come up. Would you be surprised that plants are 90 percent of black bears’ diet year-round? Besides skunk cabbage, in spring bears feed on grasses, sedges, shoots, lush greenery, leftover nuts, and occasional deer fawns.

As the seasons progress, black bears’ natural diet changes with what’s available in their environment. For example, in late summer-fall, bears go for corn and apples, nuts (acorns, beech nuts, hickory nuts), and any deer carcasses they might find. The bears go to upland forests, fields, and orchards for these foods.

What about your yard? Meghan warns that black bears can be attracted year-round to food associated with humans. In other words, bird seed, suet, pet food, garbage, compost, chickens in coops, and bee hives, if they can get at such foods.

She urges residents to avoid unintentionally attracting black bears with these foods. That means removing birdfeeders, not leaving pet food outside, securing garbage and compost, and protecting chicken coops and beehives with electric fencing.

“There is no safe time of year or time of day for a bird feeder,” Meghan explains. Bird feeders are number one in attracting bears to homes. She advises using native plants and clean bird baths for birds instead.

What besides food influences where bears go and what they do? Male black bears, or “boars”, weighing 350-500 lbs, lead solitary lives, wandering and feeding alone. The lives of females, or “sows,” weighing 140-300 lbs, are focused on producing and raising cubs (average 2-3) every two years.

In the first of two years, a female mates during the breeding season (mid-May to early July). She then spends summer-fall eating to gain weight for winter hibernation and pregnancy. Her fertilized eggs are inactive, in part of a process known as delayed implantation. Around November 1, she retreats to a den. It might be a cave, crevice, thick brush pile, or hollow under a stump or fallen tree. The fertilized eggs now develop. Cubs are born in the den (mid-January to early February). Around April 1, the female and cubs leave the den. Right away, cubs learn to find safety by using their long claws to climb trees.

In the second year of the cycle, female and cubs stay together. The cubs, now “yearlings,” learn how to take care of themselves (April to October). Then the female and yearlings go into a den (November-December) for a second winter together. They come out of hibernation and leave the den (mid-February to mid-March), eager for food. By May-June, the yearlings are ready to be on their own. The female chases them off. Another breeding season and new 2-year cycle begin.

Black bears are a subject of research. Meghan noted that since 1980, MassWildlife has been continuously monitoring our state’s black bear population. In a “collaring” study, about 40 female bears wear radio-tracking collars that enable biologists to track them and collect information year-round. Meghan herself is among the researchers who have visited bears in their winter dens during hibernation to collect data such as weight and sex. (They do this after the sleeping bears have been chemically immobilized.) In some cases, researchers have data on four or five generations of bears. A bear with a collar or a blue ear tag is one that has been studied.

Other information comes from studies of the number of bears killed on roadways or by hunters (during fall bear hunting seasons), and the number of calls from the public about bears. All these studies help researchers understand population size and growth, how bears use developed areas, and where bears travel and cross roads.

What if a bear visits your yard? Meghan says the presence of a bear is usually not an immediate threat. When the bear leaves, check your yard for – and remove – food sources that may have lured the bear into your yard.

What if you see or meet a bear on a hike? “Keep your distance, leash your pet, don’t run, and leave calmly,” Meghan says.

MassWildlife’s goal for black bears in Massachusetts is “a healthy bear population feeding on natural foods and using natural areas, living compatibly with the human population.”

Want more information? Watch Westborough TV’s video of Meghan’s recent “Living with Bears” talk for the Westborough Community Land Trust. Check out our past Nature Notes, “Get Ready for Black Bears.” Go further with Meghan’s MassWildlife article, “Loving Wildlife to Death: Good Intentions, Bad Outcomes”.

Links to more information from MassWildlife: avoiding bear conflicts, Electric fencing, protecting chickens; protecting hives; hiking & camping'; bear encounters.