Black Bears on the Move

Perhaps you’ve read some recent news items about black bears showing up in areas where they normally wouldn’t be seen. One of the most notable incidents was the young male bear that was found asleep in a tree early one morning last week on the Rochester Institute of Technology’s Henrietta campus, just a few short miles from downtown Rochester. New York State Department of Environmental Conservation wildlife personnel successfully tranquilized, captured, and relocated the yearling to a more appropriate place: Rattlesnake Hill Wildlife Management Area (WMA) in southern Livingston County, where he will have more than 5,000 wild acres to roam. But whether or not he stays there is another question.

All black bears are on the move at this time of year for various reasons. New cubs, which are born in their mother’s winter den in late January or early February, are now old enough to keep up with her as she wanders through her habitat in an effort to fatten up after a winter without eating. Females, or sows, typically occupy a 10-square-mile territory. Cubs remain with their mothers for a year-and-a-half and they all den together again the following winter.

June and July is the mating season for black bears and adult males, or boars, are on the move looking for love. A boar’s territory can encompass 100 square miles and he will mate with as many females, or sows, as he can find. These are the only two months that male and female bears tolerate each other. They do not associate at all at other times of the year. At the same time, sows are dispersing their yearling cubs so that they can mate again. During the months of courtship, it would not be unusual to see a pair of black bears at any time during the day. I photographed the bears in the accompanying image in my yard in mid-June 2008.

It must come as a shock to any young bear that – after a year-and-a-half of motherly love – it is given a swat and chased away. But that’s nature’s way of preventing inbreeding among local bear populations. And it is the primary reason that yearlings, and especially young male bears, are on the move. As they wander into the established territories of other boars – perhaps even in Rattlesnake Hill WMA – they are apt to be swatted and chased away again, causing them to sometimes wander aimlessly. Young males are particularly prone to covering plenty of ground as they search to establish territories of their own. This period of dispersal is the reason for so many black bear sightings during the late spring and early summer months.

The female black bear only comes into estrus once every two years. She is promiscuous and will mate with more than one male during the mating season. Through a unique biological process known as delayed implantation, her fertilized eggs remain dormant until she enters her winter den in November or December. When she gives birth in mid-winter, she may deliver anywhere from two to five cubs – each potentially having a different father – depending on how many times she was bred.

 


adamski_profile_Apr21photo and story by John Adamski