They're not exactly the smoothest criminals in town.

The half-dozen bears scrounging for food in the Issaquah Highlands have left a trail of glaring clues in their wake since March: muddy paw prints, tufts of fur, droppings.

Now they've discovered a new treasure trove in the city's Central Park: a group of six to eight garbage cans stuffed with scraps to feed their insatiable appetites.

The padlocked doors protecting the cans are no match for the hungry creatures, said Al Erickson, city parks manager. Parks officials are looking to invest in some bear-resistant garbage bins at $1,000 each to replace the current ones.

"The bears tear the doors apart by brute force," Erickson said. "We don't even lock the doors now."

And they're getting bolder. Yesterday, a black bear was spotted rifling through the trash at 2 p.m., Erickson said.

"For them to be out in the middle of the day, it's unusual," he said, adding that bears generally look for food in the mornings and evenings. "This type of behavior shows they're getting suburbanized."

Black bears are omnivores, which means they'll eat almost everything, from grass to berries and even dead animals' carcasses. Adult males grow to 5 to 6 feet and weigh an average of 225 pounds. Females can weigh up to 130 pounds.

The state Department of Fish and Wildlife says black bears are usually loners that avoid people. While its Web site notes that "attacks on humans are extremely rare," encounters and sightings have increased in recent years because of human encroachment on the bears' habitat.

The Issaquah bears live in the 14-acre wooded area around the Highlands. Over the years, they've become a regular part of the landscape during the summer, said Vicki Stier, executive director of the Issaquah Highlands urban village.

"People are in awe of seeing the bears," she said. "It's mating season for them, and they're back visiting after a long winter's sleep. Up here, people just realize that it's a part of the wildlife."

But for those with small children, wandering black bears can be unsettling. To minimize the risk of attack, state officials often trap bears and relocate them to less-populated areas. This can involve some creative measures.

Last week, for instance, state officials set out 20 dozen Krispy Kreme doughnuts as bait to catch a bear near Cascade Ridge Elementary School in Sammamish. The school warned children and sent newsletters to families.

In Issaquah, Erickson is penciling out the numbers for next year's budget to see how many bear-proof garbage cans the department can afford. It wasn't an expense anyone planned, but he's not complaining.

After all, he said, "[The bears] were there first. Then here we come with our houses. ... The bears are just trying to eke out a living."

Sonia Krishnan: 206-515-5546 or skrishnan@seattletimes.com