Boulder had its first bear sighting of the season this weekend — along the South Boulder Creek Trail — but it likely will be June before bear-resistant trash cans are available for residents on a large scale.

Val Matheson, the city's urban wildlife coordinator, said the city is working closely with area trash haulers about the implementation of an ordinance passed in March by the Boulder City Council that requires residents west of Broadway to have bear-resistant cans, starting this year with those who have alley trash service.

Matheson said bears start to wake up now, but they don't usually come into town very much until May or June, and spend most of the summer in the mountains.

Bear activity picks up again in August through October.

The Boulder City Council passed the ordinance requiring bear-resistant trash cans after Colorado Parks and Wildlife officers killed four bears in Boulder last year. Each of those bears was strongly habituated to eating from trash cans.

Bear advocates and Parks and Wildlife officials supported the ordinance, though some residents expressed concerns about the cost and wondered how effective it will be.

The final cost is still not known.

At one point, Western Disposal had put the estimated cost as low as $2 a month per can if they were required over a large area of the city. More recent cost estimates from Western have put the price somewhere between $5 and $13 a month, though officials said the higher price is unlikely.

To be deemed bear-resistant, the cans have to be able to withstand an hour of assault by grizzlies at a testing center in Montana.

Western Disposal CEO Frank Bruno said Monday that the company's first test was not successful, at least in part because the can turned out to have a small crack in the bottom. The bear did not open the retrofitted lid, but it did crack the can open from the bottom.

Bruno said the company modified its design, and this week is sending cans back to the testing center.

If the company cannot find a retrofit that can be certified in the next month, Western will buy bear-resistant cans from one of the companies that already make them.

Bruno said Western Disposal knows it does not have an indefinite amount of time to find a retrofit that works, and the company is working closely with the city.

However, Western does have an approved lid design for its Dumpsters.

Matheson said no one will be ticketed until the bear-resistant trash cans have been available for a sufficient time period.

"We want to make sure that in May we are announcing when and how the carts will be available so people have adequate time to get the carts and start using them," she said. "There won't be tickets written until people have that opportunity."

Contact Camera Staff Writer Erica Meltzer at 303-473-1355, meltzere@dailycamera.com or twitter.com/meltzere.