Wildlife officials were hoping Tuesday night that a mother bear and two cubs that had climbed into the upper boughs of a tree in the backyard of a University Hill home would return to the foothills overnight without further interaction with people.

The sow and her cubs climbed the tree, in a backyard near 11th Street and Aurora Avenue, on Tuesday morning after a Boulder code enforcement officer encountered them in an alley searching for trash to eat, officials say.

The adult female was tagged previously, in October 2011, according to wildlife officials, and would be put down if wildlife officers had to further intervene in the situation.

If action is taken against the adult bear, it is not yet known what would happen to the cubs. A determination would have to be made by wildlife officers as to whether the cubs could survive on their own.

"We're going to try to give this gal every chance we can to get out safely," Colorado Parks and Wildlife spokeswoman Jennifer Churchill said.

Churchill, noting that it is the time of year bears typically begin increasing their food intake in advance of hibernation, lamented that the sow had identified alleys in Boulder as a reliable place to find a meal and may be passing on that behavior to her cubs.

"It's a consistent food source, and she's got young mouths to feed," Churchill said. "We definitely don't like to see a sow teaching her cubs to eat garbage because they aren't learning their natural behaviors to go out and find food in the wild."

Curious onlookers stopped by the area Tuesday afternoon. Volunteers on the scene were instructed to make noise whenever it appeared one of the bears might be leaving the tree in hopes they would stay put until nighttime, when they could leave without much notice.

Brigid Sanner, of Broomfield, was one of the volunteer bear sitters. She rattled an aluminum water bottle with a stone inside of it to scare the bears into staying put.

Using the sow's tag as a reference, Sanner said she saw the same three bears last week when she was hiking Boulder's McClintock Trail at Chautauqua.

"They were where they were supposed to be," she said. "She was eating, and they were playing."

District Wildlife Manager Kristin Cannon said an increasing number of University Hill residents have invested in bear-resistant trash cans, but bears are still attracted to the area by the promise of an easy meal.

"There is still plenty of accessible garbage," Cannon said. "More and more people are being educated, but with CU students it's like a new group of people every year."

Cannon noted city codes prohibit placing trash out on the curb until 5 a.m. the scheduled day of pickup. Residents can keep trash in alleyway trash cans, but if animals are able to get into them, residents can be ticketed, Cannon said.

She said University Hill residents should also make sure they are picking up any fallen fruit from trees in their yards and should bring in bird feeders at night because they also tend to attract bears.

For more information on co-existing with bears in Colorado, visit http://bit.ly/oTO2jZ.

Contact Camera Staff Writer Joe Rubino at 303-473-1328, rubinoj@dailycamera.com or twitter.com/JoeCarmenRubino.