Millions of birds could be lost over the next 30 to 50 years due to oilsands development in northern Alberta, according to a report released Tuesday in Edmonton.

"As many as 166 million may be lost if tar sands development continues without some kind of major change," said Jeff Wells, the lead author of the report and senior scientist with Boreal Songbird Initiative.

The report was sponsored by the Boreal Songbird Initiative, the Natural Resources Defense Council and the Pembina Institute.

The area of boreal forest which is impacted by oilsands development is "incredibly important" to birds as a breeding habitat, and a "globally important flyway" for many kinds of wetland-dependent birds, the report said.

"Virtually every facet of tar sands oil development has the potential to harm Boreal birds — many of which are migratory birds that are protected by treaty and national law," the report said.

For example, strip mining projects that are planned for about 300,000 hectares of land will result in the loss of breeding habitat for 480,000 and 3.6 million birds, according to the report.

The impact on breeding means a loss of 4.8 million to 36 million birds over 20 years; 9.6 to 72 million birds over 40 years.

In situ drilling projects, where steam is injected into the ground to heat the oilsands making it easier to extract the bitumen, will have a more dramatic impact on bird habitat because of the area of land involved.

This could result in the loss of another 777,000 to 5.8 million birds, the authors of the study said.

They claim as many as 100,000 birds could die each year from landing and drowning in the oily water contained in tailings ponds, which are the result of oilsands mining.

The report recommends a number of measures to stop the loss of bird habitat.

The authors have called on the Alberta government to stop approving projects until conservation and mitigation measures can be put in place.

Both Canada and the United States should implement and enforce laws to protect migratory birds. They also call on both governments to cease viewing the oilsands as a source of fuel, and rely on cleaner alternatives instead.

The report was reviewed by 10 scientists in Canada and the United States.

David Collyer, president of the Canadian Association of Petroleum Producers, disputes the numbers.

"In my view, the report that's been issued this morning clearly overstates and exaggerates the environmental impacts and they are in no way indicative of what we believe to be the actual impacts that are occurring today, " he said.

Collyer said the government and regulators have more accurate numbers which suggest the impacts are much smaller than what the report suggested.

He said the total area represents only about 0.1 percent of Canada's boreal forest, adding the industry is taking steps to mitigate the impacts of strip mining and in situ drilling.

"The industry remains very focused on environmental protection and we're taking significant steps to improve our environmental performance," he said.

"But at the same time we have to look at the economic benefit that comes from oilsands activity and broader oil and gas activity in the province — and take a more balanced view."