The B.C. government has approved the shooting of one species of owl in a last-ditch effort to save their endangered cousins, as the number of northern spotted owls continues to decline decades after they became the mascot of the "War in the Woods" over old-growth logging.

Northern spotted owls are on the brink of extinction in Canada, with only 10 birds remaining in the wild in southwestern B.C., according to some estimates.

The situation is so grave that over the past five years the provincial Forests and Lands Ministry has relocated 73 and authorized the shooting of 39 barred owls, the larger and more aggressive bird encroaching on the spotted owls' limited habitat.

"Barred owls have invaded all spotted owl habitat," said Ian Blackburn, the provincial government's spotted owl recovery co-ordinator.

5-kilometre radius only

Relocation or elimination of barred owls is limited to a five-kilometre radius around areas where spotted owls have recently been confirmed, or areas being considered for reintroduction from a captive breeding program.

A northern spotted owl sits in a tree in the Deschutes National Forest near Camp Sherman, Ore. (Don Ryan/AP)

"Without this, it is likely that the wild population would be extirpated before we have sufficient captive-bred young to release -- which would significantly hurt the chances of survival for the released birds," Blackburn said in an email.

Preliminary results show that up to 13 new spotted owls — eight adult and five young — were discovered within nine of 17 sites where barred owl removals occurred, he said.

"While none of us like the idea of killing [barred owls], we all agreed that if the goal continues to be the recovery of the [spotted owl], then it is a necessary and potentially effective tool," says a 2011 internal email between members of the provincial spotted owls recovery team, obtained by the conservation group the Wilderness Committee using freedom of information legislation.

Due largely to loss of habitat from old-growth logging, spotted owls were already on the brink of extinction by the 1980s when they became the mascot of the environmental movement.

Prey on spotted owls

"The long-term hope is that if we create sufficient suitable habitat and flood it with captive-bred birds, they may be able to withstand/adapt to the competition from [barred owls]," said Blackburn.

Barred owls are more adaptable than spotted owls, and compete for space and prey, according to the federal species at risk listing for the birds. They also prey directly on spotted owls and breed with them to produce a hybrid species.

"They basically push the spotteds out," said Rob Hope of the Orphaned Wildlife Rehabilitation Centre in Delta, B.C.

"They're trying to protect what spotteds are left ... trying to control where the nesting pairs are to give them a chance."

Some view the cull as a desperate measure that may be too little, too late.

"This is what happens when you drive a species right to the edge of extinction and you don't want to do the right thing, which is put aside the habitat it needs to recover," said Gwen Barlee of the Wilderness Committee.

• You can replay the live interactive conversation held Monday night on this decision and its implications with CBC News reporter Kirk Williams.