Two recent incidents involving black bears in Wisconsin have captured the public's attention.

In rural Washburn County in northwestern Wisconsin, a young bear that had become habituated to people and their residences encountered a woman outside her home and knocked her down.

The bear stood over her and pawed at her for a few moments, scratching her face and shoulder and tearing her shirt. Then it moved on. The woman, who curled into a ball to protect her unborn child, sustained minor injuries.

One day earlier, a large black bear that found itself in the City of La Crosse drew a large crowd. People followed it with cars and video cameras till it was cornered in a fenced area of Myrick Park. With nowhere to

go, the bear climbed a tree.

The crowds ignored official requests to disperse, and the bear remained agitated. When it appeared it was going to leave the tree -- in an escape attempt that likely would have necessitated running through a crowd or across a busy highway -- it was killed by two police officers

and a conservation warden.

It wasn't a decision made lightly. For more than a decade Department of Natural Resources officials in La Crosse have resisted calls to shoot bears in residential areas, seeking instead to educate people about co-existing with these magnificent wild animals.

"We've done everything in our power for 15 years to avoid shooting bears," said warden supervisor Steve Dewald. "Then this situation came up."

Both cases, wildlife experts say, demonstrate the need for wildlife to be left wild. When bears are left alone - when people refrain from feeding them and give them plenty of room - they generally do not pose a threat to human safety.

The La Crosse bear, which weighed more than 300 pounds, was a breeding boar, said Mike Gappa, one of the foremost bear researchers in Wisconsin.

"This is the time of year we see big boars showing up in places where they wouldn't normally be," said Gappa. "They do a tremendous amount of wandering right now."

The breeding season is typically from mid June to mid July with a peak around July 4. Large male bears will travel great distances to find a receptive sow, a female entering estrus.

Problems occur when such a bear unintentionally wanders into a city at night, generally by following a river corridor. Then the sun comes up, and the bear realizes something is wrong.

"They find themselves in a situation they don't want to be in," Gappa said. "Typically, what happens is the bear makes an attempt to get out of town, but crowds of people can keep cutting off exits as they attempt to get a better look at him."

With all avenues of escape blocked, the bear becomes fearful. It climbs into a tree because it feels safer there. Often, if people don't crowd too close, it feels safe enough to take a nap.

"In 95 percent of these cases, the situation takes care of itself," Gappa said. "As soon as that bear feels it is safe to come out of the tree and go home, he will. Usually they are gone in the night."

Gappa, who lives in Eau Claire, has a long history of responding to these situations. He retired from the state Department of Natural Resources six years ago after more than 30 years as a wildlife biologist and bear researcher. He is still in the field every winter, tracking and tranquilizing bears and fitting them with radio collars.

Successfully tranquilizing a bear is no job for someone without extensive experience, he said. Just being equipped with a tranquilizer gun and training is not enough, he said. Too many things can go wrong. Tranquilizers take a minimum of 15 minutes to work -- during which time a bear may thrash around and fight the drug.

This creates a logistical problem because situations like the one in La Crosse are rare. Even bear researchers, who use jab sticks to tranquilize bears in the winter, rarely use tranquilizer guns. Bear hunters are allowed to use bait under tightly controlled circumstances, but feeding bears to enhance wildlife viewing is illegal in Wisconsin.

"The last thing we want to do is encourage a bear to become unafraid or incautious around