The Alberta Energy Regulator says it is investigating reports that approximately 30 blue herons have died at an oilsands site.
A news release from the regulator says it has sent staff to the Syncrude Canada Mildred Lake mine site, north of Fort McMurray, to assess the situation.
The cause of the deaths is still under investigation.
Will Gibson, a spokesman for Syncrude Canada, said the company is co-operating with the energy regulator as well as with provincial fish and wildlife officials and Environment Canada.
"We're investigating this incident to determine what happened," Gibson said Saturday.
The energy regulator's incident report web page says Syncrude notified it that the birds were discovered at an "abandoned sump pond" on Friday.
The birds were found near a pump house, but Gibson wasn't able to say what the pond contained, or whether the birds were coated in oil.
He said 29 birds were found dead. One additional bird was euthanized on the order of Alberta Fish and Wildlife.
Gibson said the bird deterrent system at the facility was fully operational at the time.
The regulator said that wildlife deterrent programs, including those at the Mildred Lake, are inspected regularly to make sure they're working following previous bird deaths at oilsands facilities.
More than 1,600 ducks died after they landed on a toxic Syncrude tailings pond in northern Alberta in 2008, and the company was fined $3 million.
Two years later, more than 550 birds had to be destroyed when an early winter storm forced them to land on waste ponds belonging to Syncrude and Suncor.
Gibson said the deterrent system uses radar to detect birds. It then activates propane-fired noisemakers as well as mechanical falcons to scare the birds away.
There's also human staff that will respond if birds are observed in areas of open water, Gibson said.
"We've worked at continuously improving our deterrent system," Gibson said.
According to the Canadian Wildlife Federation's "Hinterland Who's Who" website, the overall great blue heron population is healthy and scientists estimate there are tens of thousands of them in Canada.
It says the birds stand over a metre tall with their heads outstretched. Both female and male birds incubate the eggs and feed the young.