BOULDER, Colo. -- A black bear was spotted running through a back yard in Boulder early Monday morning.

Open space rangers responded to the neighborhood in the 1800 block of Lehigh Street but didn't find the bear.

Lisa Marti spotted the bear just after 6 a.m. and said it did not stop in the back yard.

"I just saw a bear cub walk by," Marti said. "I thought it was very interesting. I'm not surprised because one of the wildlife agencies came by a couple months ago and dropped off literature and said (bears) were in the area."

It is not uncommon for bears to be spotted in the early-morning hours in areas so close to the foothills, city of Boulder Open Space officials said.

"If you see a bear in your back yard, of course, you want to get everybody inside and that includes animals -- if you can find your cat and if you can find your dog," said Julie Johnson with Boulder Open Space.

Officials said bears are attracted to trash cans and places where human food can be found.

"Please don't leave your trash out. If your trash comes on Monday morning don't put the trash out on Sunday evening, because that's an attraction," Johnson said.

There is a $1,000 fine in Boulder for residents who leave trash out.

"It just seems like there has been a lot more wildlife coming down from the mountains in the last three years," Marti said.

Wildlife officials said bears are mainly vegetarians and are not interested in humans. So, if confronted by a bear, a person should back away slowly and talk in low voice.

A person should never run away, which will trigger the bear's instinct to give chase.

Officials said keeping a clean car can help keep bears away. They said residents should never leave trash, food, pet food or coolers in a car because bears have been known to open doors and break windshields when they are hungry.