Hawadax Island (Aleut: Hawadax) is an island in the Rat Islands archipelago of the western Aleutian Islands in the U.S. state of Alaska. The island was formerly known as Rat Island until May, 2012 when it was renamed Hawadax Island, which is an Aleut name meaning “entry” and “welcome.” The island has a land area of 10.3126 sq mi (26.7095 km²) and no permanent population. It is within the Alaska Maritime National Wildlife Refuge. It is 15 kilometres (9.3 mi) in length and 5 kilometres (3.1 mi) in width.
The former name is the English translation of the name given to the islands by Captain Fyodor Petrovich Litke in 1827 when he visited the Aleutian Islands on a voyage around the world.
The Rat Islands are very earthquake-prone as they are located on the boundary of the Pacific and North American tectonic plates. In 1965, there was a major earthquake with the magnitude 8.7 in the Rat Islands.
The rats arrived on the island before 1780 due to a Japanese shipwreck. Since then, the rats have had a devastating effect on local seabirds that have no natural defenses against the rats. Invasive rats are also present on 16 other islands in the Aleutian chain.
In 2007, the U.S. Fish and Wildlife Service, which manages the Refuge, was formulating plans to eradicate the rats, without negatively affecting other species. Scientists considered the island a test case for other eradications in less isolated environments. The eradication plan is modeled on a successful one to eliminate the Arctic fox from various Aleutian islands, where they were deliberately introduced for breeding.
In June 2009, the island was declared rat-free for the first time in 229 years, although the site will be continually monitored for another two years for confirmation. In the preceding autumn, helicopters dropped brodifacoum poison onto the island from buckets for a week, which seems to have eliminated the rat population. Signs show that several species of birds, including Aleutian cackling geese, ptarmigan, peregrine falcons and black oystercatchers, are starting to nest again on the island. Although the associated nontarget mortality was significant. Some nontarget mortality was expected, but the actual mortality greatly exceeded the predicted mortality. Forty-six Bald Eagles died (exceeding the known population of 22 Bald Eagles on the island); toxicological analysis revealed lethal levels of brodifacoum in 12 of the sixteen carcasses tested. Of the 320 Glaucous-winged Gull carcasses collected, toxicology tests implicated brodifacoum in 24 of the 34 tested. Fifty-four carcasses of another 25 bird species were found.
- Campbell Island, New Zealand, the largest successful rat eradication.
- Bergsland, K. (1994). Aleut Dictionary. Fairbanks: Alaska Native Language Center.
- "Feature Detail Report for: Hawadax Island". United States Geological Survey Board on Geographic Names. Retrieved 31 May 2012.
- Rats Wipe Out Seabirds on Alaska Island
- Ebbert, S.E.; Byrd, G.V. (2002). "Eradications of invasive species to restore natural biological diversity on Alaska Maritime National Wildlife Refuge". In Veitch, C.R. Turning the Tide: The Eradication of Invasive Species : Proceedings of the International Conference on the Eradication of Island Invasives. The World Conservation Union. ISBN 2-8317-0682-3. Retrieved 2007-10-03.
- "Biologists aim to wipe out Rat Island". Reuters. October 2, 2007. Retrieved 2007-10-02.
- Alaska's Rat Island rat-free after 229 years
- Steve Ebbert and Kathy Burek-Huntington. 2010. Anticoagulant Residual Concentration and Poisoning in Birds Following a Large-Scale Aerial Application of 25 ppm Brodifacoum Bait for Rat Eradication on Rat Island, Alaska. Proceedings of the 24th Vertebrate Pest Conference (R. M. Timm and K. A. Fagerstone,Eds.). Published at Univ. of Calif., Davis.
- THE RAT ISLAND RAT ERADICATION PROJECT: A CRITICAL EVALUATION OF NONTARGET MORTALITY. PREPARED FOR ISLAND CONSERVATION, THE NATURE CONSERVANCY and the U.S. FISH AND WILDLIFE SERVICE, ALASKA MARITIME NATIONAL WILDLIFE REFUGE. PREPARED BY THE ORNITHOLOGICAL COUNCIL. Final report issued December 2010
- THE RAT ISLAND RAT ERADICATION PROJECT: A CRITICAL EVALUATION OF NONTARGET MORTALITY
- Rat Island Invasive Rat Eradication Project Environmental Assessment
- Rat Island: Block 1140, Census Tract 1, Aleutians West Census Area, Alaska United States Census Bureau