The Canada warbler population has declined by 80 per cent over the last 40 years, according to the Boreal Songbird Initiative. (Jeff Nadler/Boreal Songbird Initiative)

Songbirds living in the boreal forest are declining at a rapid rate and need protection by federal and provincial governments, according to a group of environmentalists and scientists.

Migratory birds dependent on the 5.6 million square kilometres of boreal forest, such as the Canada warbler, rusty blackbird and olive-sided flycatcher, have faced particularly steep declines, according to the Boreal Songbird Initiative, which has collected more than 60,000 signatures on a petition calling for greater protection for the forest.

"The boreal forest is widely regarded as the songbird nursery for the Americas," Ontario Nature executive director Caroline Schultz said at a press conference at Queen's Park in Toronto on Tuesday.

"Millions of birds migrate there to nest and breed in Ontario alone. We cannot afford to lose any more of this precious habitat than we already have," she said.

Ontario Nature was one of several groups across the country that planned events in six provinces and the Northwest Territories on Tuesday to call attention to the declining songbird numbers.

The groups said the boreal forest, which stretches from Newfoundland in the east through to the Yukon and into Alaska, is under threat from logging, mining and other industrial activities, which have fragmented the landscape, particularly in the southern portion of the forest.

Ontario Nature said logging in Ontario alone can destroy an estimated 45,000 migratory bird nests in a single year. Only 10 per cent of the forest in the province is protected, the group said.

In the summer of 2008, Ontario Premier Dalton McGuinty pledged to protect 225,000 square kilometres of the province's northern boreal forest, but the government has yet to pass legislation to fulfil that pledge, Ontario Nature said.

Ontario's pledge to protect the forest came a year after the Boreal Songbird Initiative, in conjunction with the International Boreal Conservation Campaign and the Canadian Boreal Initiative, collected signatures from more than 1,500 scientists calling on all levels of government to protect the forest.

Forest holds 186 billion tonnes of carbon

In addition to its unique ecosystem, the groups said the forest was the largest carbon storehouse in the world, holding about 186 billion tonnes of carbon, or the equivalent of 27 years of global carbon dioxide emissions from burning fossil fuels.

If migratory birds are any indication, the forest ecosystem is in trouble, said Bridget Stutchbury, a Canada Research Chair in ecology and conservation biology at York University.

The population of rusty blackbirds, the northernmost breeding blackbirds, has declined by 90 per cent in the last 40 years, the group said, while in Ontario, olive-sided flycatcher numbers have fallen 46 per cent in the last 10 years alone.

Other birds that have seen their numbers fall by more than three-quarters in the last 40 years include the Canada warbler, American black duck and evening grosbeak, according to data taken from the Canadian Breeding Bird Survey.

Canada will need to safeguard the boreal forest and its songbirds from further encroachment, Stutchbury said in a statement Tuesday.

"The dramatic decline in migratory songbirds warns us that our forests are under siege," said Stutchbury.