With the aim being to kill every single rat, 400 bait stations have been set up on Arichika and Bischof Islands in Gwaii Haanas National Park Reserve on Haida Gwaii (formerly Queen Charlotte Islands).
The rats are responsible for decimating songbird and seabird populations on the islands, says Gregg Howald, North America regional director of Island Conservation, one of the organizations involved in the project along with Parks Canada and others.
After ingesting the poisonous bait from the stations, which are placed at 50-metre intervals, the rats have time to retreat to their burrows before they die, says Howald. However, crews will be checking to collect any that die above ground.
Getting rid of the rats is part of a project that aims to restore seabird colonies—particularly ancient murrelet populations—that were hard hit by oil leaking from the S.S. Jacob Luckenbach, a freighter that sank in 1953 about 17 miles southwest of the Golden Gate Bridge in Los Angeles.
In 2002, the Luckenbach was identified as the source of many mystery oil spills that occurred periodically during winter storms. The spills resulted in the oiling of thousands of seabirds along northern California beaches for decades.
Haida Gwaii is a major nesting place for ancient murrelets, and with the rats gone for good the birds, listed a species at risk by Canada, will have a better chance of rebuilding their numbers.
“Over half the world’s population [of ancient murrelets] breeds in Haida Gwaii,” says Howald. “We’re creating more breeding habitat for them.”
It is believed that rats initially arrived on the islands in the late 1700s, probably brought there by the Spanish who first made contact in 1792. The rats jumped ship and made the islands their home.
Voracious Feeders
“Rats have been implicated in roughly 40 to 60 percent of all wild bird and reptile extinctions. And it’s not only restricted to birds and reptiles—they feed on everything from intertidal organisms like algae and seaweed to lipids and snails. … And plants as well have been certainly in decline because of rats, and that puts pressure on those ecosystems.”
Island Conservation has protected 305 native species from extinction on 48 islands worldwide. The organization is currently working on the Scott Islands in B.C., which support around two million seabirds.
“There’s the potential to increase the habitat for those seabirds in that region very significantly by removal of introduced predators—mink and raccoon—that were put on the islands in the 1930s,” says Howald.
The story goes that the mink and raccoon were introduced to establish a fur industry, in part because the islands had an abundance of seabirds that the animals could feed on.
“There’s history of that as well with the Arctic fox on the Aleutian Islands,” says Howald. “The Russians introduced the Arctic fox deliberately to these islands with massive seabird colonies to provide and sustain—naturally sustain—that Arctic fox population so they could harvest them.”
The rat eradication program on Bischof and Arichika will run until the end of September, with surveillance using remote cameras continuing for two years to make sure no rats remain.
A similar program was used to successfully eradicate rats from Langara Island in Haida Gwaii and St. James Island, a B.C. Gulf island.
About 85 percent of the world’s islands have had or continue to have introductions of rats, both on populated and unpopulated islands, Howald says.
