Wildlife officers in Fort McMurray have killed two black bears and captured and relocated two others that were roaming in and around the fire-damaged city.
Alberta government spokesman Brendan Cox said that May 3 — the day more than 80,000 people were forced to flee a raging wildfire — also happened to be garbage day for most residential neighbourhoods.
The stinky trash left on city streets attracted animals looking for an easy meal.
"Wildlife is attracted to unnatural food sources," Cox said from Edmonton. "Bears, for example, can smell rotting garbage from kilometres away."
There have been 30 complaints about bears in the city in the past three weeks, he said. Although the city remains empty of residents, there are firefighters and others there working to restore utilities, repair and clean the city's hospital and reopen pharmacies and grocery stores.
About 2,400 buildings were destroyed but fire crews managed to save almost 90 per cent of the oilsands city.
Workers have cleaned up most of the garbage, Cox said.
But foul odours will soon be returning.
Residents may be allowed back into the community starting June 1, and those who didn't lose their homes to the flames will still need to clean up and throw out rotting food inside their refrigerators and freezers.
"We would ask returning residents to ensure their appliances, garbage or any other attractants are secured until it can be picked up or delivered to a proper waste management facility," Cox said.
A government guide on the phased re-entry process also advises people not to leave their doors open in case animals wander inside.
The Fort McMurray area has always been popular for bears, said Cox.
About eight wildlife officers remain in the community. They have set up bear traps in neighbourhoods of concern and will also be proactively placing traps in areas known to be frequented by bears outside the city to "intercept" them, Cox said.
"Officers are going to continue to be focused on this for the forseeable future."