CBC News, May 19, 2016 by Maryse Zeidler: Parks Canada says it has wiped out invasive rats on two islands in Haida Gwaii, B.C., helping important seabirds species recover by doing so.
"It's fair to say that I am over the moon about it," said conservation manager Tyler Peet. "It was a lot of work and we had a lot of extremely valuable help from international partners."
The news comes on the heels of the first State of North America's Birds report, that found one third of birds in North America are threatened with extinction, especially ocean birds.
The rats threaten seabirds like ancient murrelets — a species at risk that is culturally significant to the Haida Nation — by eating their eggs and chicks.
"For me that is the single most important piece of this success story," Peet said. "We've been able to rid some pretty key habitat of an invasive species."
He said the ecological systems on the islands are slowly recovering, including seabirds, crabs and some vegetation.
Efforts to eradicate the rats began in 2009, targeting four islands in Gwaii Haanas National Park Reserve selected for their small size and distance from other islands in the archipelago — rats are prodigious swimmers, which is part of what has eased their spread in the sensitive ecological area.
Peet said the islands were so infested, Parks Canada officers would warn campers against staying there because they had heard so many reports of people woken up in the night by rats scurrying about their tent.
Death from above
The rats were killed by air-dropping poison pellets across three of the four targeted islands. The one island where the poison was spread by hand was reinfested.
"That was an unfortunate outcome that we've been monitoring since," Peet said.
One of the concerns for those involved with the project was if the poison would kill other species — either by directly eating it, or by eating rats that had.
Peet says only 120 other animals were killed by the poison, most of them crows and ravens, but there were some sparrows and species of thrush as well.
"One of the major concerns was that eagles would be impacted," Peet said. "Absolutely no bald eagles were recovered during the eradication operation."
Now that the project has been deemed successful, it's possible it could be extended to other islands in Haida Gwaii, but Peet says there's still a lot of work to do.
For now, Parks Canada and its partners will continue to monitor the ecological recovery of the rat-free islands. It also plans to develop a biosecurity program to promote awareness and prevention.