Rats and Wildlife

They Came on a Sailing Ship

Norway and roof rats are not native to Alaska or even to North America. Alaska was still part of Russia in 1780 when the first rats are believed to have reached Alaska on a Japanese sailing ship. The ship went aground on what became known as Rat Island. Now, over 200 years later, the seabird colonies that once must have flourished on Rat Island are gone, but the rats remain. Since that fateful beginning, other shipwrecks, the creation of harbors and docks allowing boats to tie up, and especially World War II, brought rats to many of the towns of Southeast Alaska and to more than a dozen inhabited and uninhabited islands of the Aleutians.

Few Predators but Lots of Prey Greet the New Rats in the Aleutians

Before the rats came, there were no land mammals on most of the Aleutian Islands, so the rats had few competitors and no predators other than an occasional owl or eagle. Rats are tough, adaptable and, in the Aleutians, capable of living in the wild away from towns and harbors. On the dozen or so Aleutian islands where rats have become established, they roam over much of the islands, but concentrate along the coastlines.

Stocking Up on Auklets

What the shipwrecked rats found was an abundance of food – dense colonies of nesting seabirds, intertidal organisms, insects, spiders, lush vegetation and seeds. Being omnivores, rats could find something to eat in every season. They are capable of killing and stockpiling birds for winter food and switching to alternative food sources when the birds are gone. As many as 20 auklet bodies have been pulled out of one rat den.

Birds at Risk: Big, Small, the Abundant and the Rare

Rats can kill even very large birds, but the small ground and burrow nesting birds in the treeless Aleutians, Pribilofs and Southwest Alaska are most at risk.

Some islands have tremendous seabird colonies of more than a million birds. Should rats become established on a bird-rich island such as Buldir or Bogoslof, millions of birds would be killed. At least 14 species on Audubon’s Alaska Watchlist for declining species nest on islands at risk of rat introductions. Whiskered auklets, red-legged kittiwakes, and McKay’s buntings are just some of these special birds. Rats in Alaska may kill in one year as many birds as were killed by the Exxon Valdez spill. World wide, rats have been responsible for about half of all bird and reptile extinctions.

Rats Still Leave Sinking Ships

Fierce storms producing gale force winds and seas of 30 feet or more, ferocious tidal currents through island passes, and uncharted rocks and reefs have always added an element of risk to ship travel in the North Pacific and Bering Sea. Today, the islands of the Aleutians remain at great risk for further rat introductions through shipwrecks. An average of two shipping mishaps a year occur on or adjacent to the Alaska Maritime National Wildlife Refuge due to its location in the midst of one of the world’s busiest shipping lanes, the North Pacific Great Circle Route. Over 3,000 ship passes by large container ships and freighters through the Aleutian Islands and the refuge happen every year.

Defending the Islands

A specially trained “rat spill” response team of Fish and Wildlife Service employees and partners is the first line of defense against rats fleeing sinking ships. Shipwreck response kits strategically located along the coast are used by the team against rats on or fleeing a sinking ship. The kits contain everything needed to kill rats attempting to go ashore. When ships wreck on rat-free islands, crews put beach defenses in place to protect the native wildlife. Should the rats make it to shore and began reproducing, removal may not be possible or would be extremely expensive and difficult.

The Pribilofs: Island Paradise at Risk

Swirling clouds of seabirds and beaches of bellowing fur seals greet visitors to the Pribilof Islands, one of the richest wildlife areas in North America. They are also home to Unangan (Aleut) people in the villages of St. Paul and St. George on the islands of the same names. The bird cliffs are part of the Alaska Maritime National Wildlife Refuge and the fur seal rookeries are also federal land protected by the National Marine Fisheries Service. Luck, isolation, and the lack of harbors protected the Pribilofs from rats for more than a century. In the 1990s both islands developed harbors and, for the first time, ships were able to tie up to docks. At the same time, fishing activity exploded around the Pribilofs raising the specter of an invasion of hitch-hiking rats.

Pribilovians Get Tough on Rats

The communities of St. Paul and St. George working with partners started an aggressive island defense program which is a model for Alaska. On both islands, Ecosystem Conservation Offices of the Tribal governments maintain a series of bait stations throughout their harbors and the dump with the goal of stopping any rat that jumps ship. In 15 years of maintaining the traps, St. Paul has caught 6 rats which confirm that rats are moving between ports on boats. In addition, St. George and St. Paul, created city ordinances banning any ships with a rat aboard from city waters and the city dock. The cities can inspect vessels and have ejected vessels from the harbors. Local commercial fish processors are required to have rodent prevention programs, and the Tribes offer rat prevention kits to boats. So far, this strategy has worked saving three million seabirds from rat predation and nearly a million fur seals from the possibility of rat-borne diseases.

Righting the Wrongs – Island Restoration

Norway rats don’t belong on National Wildlife Refuges. As introduced predators, they upset the native ecosystems, prey on native wildlife, alter habitats and generally destroy the natural biodiversity National Wildlife Refuges are charged with protecting. It is too late for prevention on the dozen or more major islands in the Alaska Maritime National Wildlife Refuge where rats have become established. Native bird populations have been decimated on many of these islands. The only way to restore the native species is to get rid of the non-native one – the rat.

Making Birds

Biologists confirmed that Rat Island, a remote island in the Alaska Maritime National Wildlife Refuge, is now rat-free. The report comes after two years of careful field monitoring at Rat Island, where the invasive predator decimated native bird populations by preying on eggs and chicks and altered the native ecosystem in numerous ways. Restoring habitat on Rat Island to benefit native wildlife is the largest rat eradication ever undertaken in the Northern Hemisphere and the first in Alaska. The eradication of the non-native rats took place in September of 2008 after four years of planning. The restoration of the 10-square-mile island was accomplished by Island Conservation, The Nature Conservancy and the U.S. Fish and Wildlife Service. With the rats gone, restoration partners and the Aleutian Pribilof Island Association agree that an Aleut (Unangan), name was a fitting tribute to the restored island. The U.S. Board on Geographic Names, at its May 10, 2012 meeting, approved the proposal to change the name of Rat Island to Hawadax Island in the Aleutians. Hawadax (pronounced “how AH thaa”) is a return to the original Aleut name, in acknowledgement of the absence of rats—a return the island’s previous ecological state prior to European/Japanese contact. The word ‘Hawadax’ roughly translates to “those two over there” as in “the island over there with two knolls”, referring to two modest hills on the island. Learn more.

The Mystery of Kiska Island

Only one island with rats still has any significant number of birds left and that is remote, uninhabited, Kiska Island. Auklets numbering in the tens of millions swarm this island in spite of the rats which have been on Kiska since World War II. Theories abound as to why these birds are still left and as to how long they can last. Perhaps the sheer size of the colony partially protects the birds or possibly it took decades for the rats to migrate from the WWII bases on one end of the island to the volcanic slopes the auklets nest in. Most bird experts agree these birds are doomed unless the rats can be eliminated. No one, anywhere in the world, has removed rats from an island as big as Kiska, nearly 70,000 acres. Can the “how” and “with what money” be resolved in time to save Kiska’s auklets?