Marmots need to leave Sud Island for the birds

“Now we know there are at least some auklets still nesting on the island. The colony has potential, then, to expand from these remnant birds once marmots are removed.” – Steve Ebbert, invasive species biologist

• National Maritime Wildlife Refuge considers invasive rodent eradication

by Naomi Klouda
Homer Tribune

Few records exist about why barracks for 15 people was built on Sud Island in the Barrens in the 1940s. Even less is known about why the Alaska Game Commission stocked the 275-acre island with hoary marmots in 1930.
What is known, however, is that thousands of rhinoceros auklet once calling Sud Island home were nearly wiped out by the hoary suspects, said Steve Ebbert, invasive species biologist with the Alaska Maritime National Wildlife Refuge.
Along with Alaska Unit biologist Leslie Slater, Ebbert completed an eight-day, summer field survey of the island, and found good news. The shy rhino auklet – which only nests on two other islands in Alaska – has returned despite the marmots’ egg-eating habits and a near 20-year absence.
“We don’t know why the hoary marmot were stocked there. It is documented that the Alaska Game Commission had a lot of stocking projects, but at this point, it’s pure speculation on why,” Ebbert said. “In the 1920s they allowed fox ranching on islands and put deer on islands in Prince William Sound, Kodiak Island and even some on the Homer Spit, and later they transplanted bison, elk, beavers, muskrats, marten, mink and raccoons onto islands.”
Ebbert noted that the Post-Depression time period offers a few clues. In 1931, the federal government did a coastal survey and left its markers behind, Ebbert said. Sud, which means “South” in French, was one of the islands visited. During that time, the Civilian Conservation Corps was a government program finding ways to put people to work. And given that watchful era prior to World War II, a coastal program was enacted to report suspicious ships as American became increasingly fearful of enemy attacks on Alaska.
In their field work, Ebbert and Slater were able to find the remains of the barracks, as well as a possible weather station at the summit of Sud Island. The island is about one mile by one-half mile, making it the wind-racked Barrens’ smallest member island.
“The barracks seemed like it would hold maybe 15 people. We found the remains of a shack on the summit and some electrical or radio parts,” Ebbert said. “If 15 guys are on an island like Sud – which is not easily accessible – and there is no meat on the island, you can see the attractiveness of having it stocked that way.”

Rhino auklets
Hoary marmots are native to the Kenai Peninsula, but not to the Barrens. Cousins to the prairie dog and considered the largest member of the squirrel family, this marmot is not to be confused with the Arctic Marmot that was named by the Alaska Legislature last year as the state’s mascot for Groundhog Day.
As for eating them – like rabbits or squirrels – they would provide a food source and their fur would have made them attractive for trapping. The only problem is, the marmots hibernate from August until May, Ebbert said, which would hamper their usefulness as game.
Rhino auklets were once abundant on the island, with data recording 500 burrows by Edgar Bailey when he was a refuge biologist in 1975. In 1994, Dave Roseneau went looking for the auklets, but found no more.
Bird experts know the rhino auklets forge rookeries 210 miles away east on Middleton Island in the Gulf of Alaska and in the Semidi Islands’ Chowiet 260 miles to the west. That’s about it for their nesting territory in Alaska, other than Sud Island. In recent years, a few rhinos were reported feeding in waters during surveys from boats in the Barrens, so Ebbert and Slater’s task was to find out if the auklets were actually nesting on the island.
While counting birds and studying the island for a possible marmot eradication plan, Ebbert and Slater came upon bird burrows in the cliffs.
The burrows were unusual auklet habitat, since they were not on vegetated slopes that the auklets usually prefer. During the day, no bird was home. In daylight, seabirds are busy feeding; they don’t return to the nest until night.
“They are out fishing on the water by day, so we kept an eye out for their burrows and their chicks,” Ebbert said. “On the last day there, we found an odd place above a steep cliff. Holes were in the side of the cliff just under the vegetation layer.”
To check it out further, Leslie Slater reached down from the top of the cliff.
“I held onto her legs while she reached down as far she could into the burrow,” Ebbert said. “We were hoping to find an egg shell or feather to bring up.”
Furrowing from the top of the cliff didn’t yield any conclusive evidence, so the two biologists set up a motion-sensitive camera. With the birds returning at night to their burrows, their movement would trip off a sensor and they would be photographed.
Still, Ebbert and Slater wouldn’t know what kind of images they captured until they returned to the refuge headquarters, since they were using old-fashioned film that must be developed. Once made into prints, the biologists had six clear photos showing the cliff dwellers to definitely be rhino auklets.
“We were looking through the magnifying lens, and there plain as day was a rhino auklet,” Ebbert said. “It was a fun and interesting moment.”

Eradicating marmots
The refuge has a long-established method for eradicating introduced predators from islands. Arctic and red foxes introduced to the islands by fur trappers drove the Aleutian cackling goose almost to extinction before the U.S. Fish and Wildlife Service intervened in 1970. The goose population now numbers around 30,000, up from a low of about 600. Accidental introductions of Norway rats have occurred on many islands; an infestation caused by a Japanese shipwreck at Rat Island more than 200 years ago decimated local birds until the Alaska Maritime Refuge teamed with Island Conservation and The Nature Conservancy and conducted a $2.5-million rat eradication effort last year.
And while the refuge hasn’t before confronted a marmot extermination project, much of the process is the same.
In pre-eradication surveys, Ebbert and Slater set up grid plots and described plants, conducted marine mammal counts and bird presence in each plot. Among the tasks was figuring out where the refuge would put a camp, how much time the effort would take, testing traps and methods. The idea is to be able to monitor the restoration after the eradication, Ebbert said.
Presently, Ebbert and Slater are compiling their report. An environmental assessment is being prepared to describe the project, and will be available for public comment in January.
The refuge must conform to the National Environmental Policy Act, and – if approved – biologists could start the program next year, Ebbert said.
“The hoary marmots are not rare or threatened, and they don’t belong on Sud Island; the auklets do belong there. It’s great news the species didn’t completely move out,” he said. “It can take a longer time for some seabird species to re-colonize an island after an invasive predator is eradicated if there are no nesting birds around. But if they are already on the island, re-colonization can go much faster.”

Contact the writer
Posted by Newsroom on Nov 4th, 2009 and filed under Headline News. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

Subscribe via RSS

Subscribe via email