Syncrude and Suncor will not be charged after hundreds of migrating ducks died after landing on tailings ponds in the Alberta oilsands in October 2010.

More than 500 ducks died or had to be euthanized after coming in contact with the toxic bitumen extract in the ponds, which are formed from the excess water used to separate heavy oil from sand.

While the incident happened two years ago, the findings of an investigation now say there is nothing that could have been done to prevent the deaths.

In a report written by biologist Dr. Colleen Cassady St. Clair from the University of Alberta, a leading expert in North America on human-wildlife encounters and deterrence methods, it says strong winds and freezing rain forced the birds to land abruptly in large numbers — even though there were noise cannons in place to scare them away.

Based on the evidence gathered by provincial investigators and St. Clair's report, the Crown prosecutor in the case says there is no reasonable expectation of conviction.

The provincial government said St. Clair’s report is being used to help oilsands companies prevent more duck deaths in the future.

She suggests the position of deterrents and artificial lights may have influenced where the birds landed, and industry practice for bird deterrence had not previously accounted for the influence of light during poor weather.

The Alberta government said the industry is now working with the University of Alberta to implement electronic, field-based data recording, develop new technologies for automating bird monitoring and test new methods for bird deterrence.

The death of the 550 ducks in the 2010 incident happened just days after Syncrude was ordered to pay $3 million because of a much larger incident in 2008.

In that case, a court determined the company failed to put bird deterrents in place to scare the ducks away.

Syncrude was also ordered by the court to identify best practices for preventing bird landings on tailings ponds, which the province says is also helping to improve industry standards when it comes to bird deterrence.