The Wild Side: Keeping track of Wisconsin’s bears
We are currently in the time of year when bears are very active. We have momma bears with cubs moving about. The cubs will stay with their mother for another 12 months.
When they get to their second June, at about 16 months, young bears are run off by their mothers so they are able to breed and start the cycle again. Consequently, female bears, or sows, breed and give birth every other year. So, in June, we get a flush of yearling bears that have been run off by their mothers and are out exploring and looking for new territories to establish. Basically, they are sort of teenagers; these bears get into trouble hanging around homes, eating birdseed, garbage, handouts, whatever they can beg or steal.Many of our nuisance bear calls this time of year are yearling bears.
A sow bear will set up a territory of about 10 square miles, in which she will not tolerate other female bears. A boar (or male) bear will set up a territory of about 30 square miles, but will not defend it as aggressively as a female might.
This time of year is also the peak of the breeding season. During this time, bears can be more vocal, more aggressive, and are often less afraid of humans. Bears have earned a reputation that makes people fearful; some of it deserved, some not. Bears have an amazing sense of smell, but terrible eyesight. If they smell something that concerns them, they will try to get a better look, standing on their hind legs to get a better angle. This can be unsettling if you are the “something” the bear is studying. If a bear feels threatened or trapped, it may bluff charge you, running forward and stopping abruptly. It may swat dirt at you with its paw. It may clack its jaw and make some pretty scary vocalizations. This all means it is afraid of you, and is trying to frighten you away. Remember, if you see a bear, give it space, make sure it sees you, and do not block its escape route. They usually do not want an encounter with you.
We do our roadside bear surveys during this time of year to take advantage of the increase in bear activity and territoriality. It is a pretty simple survey. We have established one route per county. We drive the route, and every half mile we hang a small mesh onion bag in a soft-barked tree. This mesh bag is stuffed with suet. We leave these bags hang for 7 days, then go back and pull them down. If a bear visits the bait, signs will be evident. The vegetation is mashed flat from the road to the tree where the bait is hung. The bait is usually completely gone, and there are noticeable claw marks in the tree. We pull down all the material that remains and record the hit.
This roadside bear survey does not give us a precise population estimate, but rather serves as an indicator of whether the bear population appears higher or lower than previous years. For example, last year the “hit rate” on the Oneida County route was 49 percent; it was down from 62 percent in 2010. The 5 year average is 52 percent.
This study has a long history of providing bear population data; however, it is not as accurate or as useful as the information provided by our Black Bear Population Survey currently underway. You may recall that a year ago, DNR staff, the Wisconsin Bear Hunter’s Association, and a multitude of volunteers hung baits every three miles across the north. Those baits were laced with tetracycline, an antibiotic that leaves its mark on the bones of bears that consume it. With bear hunters’ help, we will collect bear ribs and teeth again this year to more accurately determine the bear population in Wisconsin.