EDMONTON - Syncrude Canada has been found guilty under wildlife laws of causing the death of 1,600 ducks in a tailings pond at its oilsands mine in northern Alberta.

"It should have been obvious to Syncrude that deterrence should have been in place in the spring as soon as reasonably possible," provincial court Judge Ken Tjosvold said Friday in his ruling.

"Syncrude did not deploy deterrence early enough or quickly enough."

In his written judgment, Tjosvold said, "I am convinced beyond reasonable doubt that Syncrude could have acted lawfully by using due diligence to deter birds from the basin ... and it did not do so."

Images of tar-fouled and suffering ducks that flashed around the world became a focal point for oilsands critics, who say the environmental cost of the oilsands is too high.

Syncrude lawyer Robert White, who said he will advise Syncrude to appeal the decision, had argued that the company was following regulations and that holding it responsible for the deaths would have dire consequences for the entire oilsands industry.

"We're disappointed today," said Syncrude spokeswoman Cheryl Robb, who said the decision to fight the charges was discussed at high levels among all of Syncrude's seven partners.

"We were very concerned that the use of these charges would have had serious ramifications on Canada's mining industry," she said. "We were concerned that it would open us up to private prosecutions from special interest groups who have said that they would seek those prosecutions."

But prosecutors Susan McRory and Kent Brown said Tjosvold made it clear that companies taking reasonable precautions won't be held liable for inevitable wildlife deaths in such facilities.

"Due diligence is a defence," said McRory, who represented the province. "The judge has found that Syncrude was not duly diligent, but has reconfirmed that it is a defence available to any corporation to prevent convictions by taking reasonable steps to avoid the offence in the first place."

Still, Robb and White held that the deaths should have been handled through regulatory fines instead of charges. Robb said Syncrude might not even have contested regulatory action.

Syncrude faced one charge under environmental law and another under federal legislation for failing to stop the ducks from landing on its 12-square-kilometre tailings pond on April 28, 2008.

The judge found the company guilty on both counts.

But White argued Friday that Syncrude cannot be found guilty twice of the same offence. "Were both convictions entered, the rule against multiple convictions would be violated," he said.

Tjosvold postponed entering the convictions into the record until White's argument can be heard by the court in August.

Sentencing has been held over until after that. The company would face fines of up to $800,000 if both convictions were allowed to stand, although the federal charge does allow for a separate fine to be levied for every dead bird.

Oilsands companies are obliged to take measures to keep migratory birds away from waste-water ponds, which contain a poisonous brew of water, clay, leftover bitumen and heavy metals.

But during the trial, court heard that the Syncrude staff assigned to get air cannons and scarecrows deployed at the pond were two weeks behind schedule that spring and didn't get going until mid-April. And, even when they did, the seven-member team couldn't do much.

Their boats were out of service and they had one truck to deliver all the equipment. They managed to get eight cannons around the pond compared with 130 the year before.

A major spring storm made things worse when it dumped almost 40 centimetres of snow in the area. The ducks had no water to land on except the tailings pond. White argued the snowstorm was freakish in timing and intensity and could not have been foreseen by Syncrude.

The birds died because they could not escape the thick black goo on top. They were eaten alive by ravens or sank like stones to the bottom.

Robb said Syncrude has taken steps to minimize the chance of that happening again. Deterence measures now operate all year round.

But Mike Hudema of Greenpeace said Syncrude and the Alberta government still have a lot to answer for.

"The Stelmach government has never looked into its own fault in this event and continues to allow multinational companies to poison and destroy large swaths of this province," Hudema said.

"These toxic lakes should never have been allowed to be created. This isn't just about the ducks. It is about health and protecting people and communities."

Tailings ponds, which now cover a total of 170 square kilometres between all oilsands operators, have long been a major point of controversy for the industry. Hundreds of millions of dollars are being spent in efforts to clean them up and reclaim them.

Last year, Alberta's energy regulator gave companies a number of restoration deadlines. But several players have already been granted extensions.

Environmentalists and academics have said the images of the struggling ducks -- together with similar distressing wildlife images from the BP spill in the Gulf of Mexico -- have increased public awareness of how difficult and risky it is becoming for industry to meet society's demand for oil.

The Syncrude project is a joint venture by several oil companies that include Imperial Oil, Nexen, ConocoPhillips, Canadian Oil Sands Ltd. and Murphy Oil.

Syncrude's Mildred Lake facility is located about 40 kilometres north of Fort McMurray.