The U.S. Fish and Wildlife Service has received laboratory results on an initial group of bird carcasses collected on Rat in late May and Early June. Examination of the livers of two bald eagles, two glaucous winged gulls, one peregrine falcon, and one rock sandpiper all tested positive for the rodenticide brodifacoum. We are in the process of analyzing all of the viable bird remains and tissue samples collected, in order to more fully understand the cause of mortalities and more effectively plan future operations in the Aleutians. Results will be released when they are available. In addition, soil and water samples were collected, and will be analyzed to more fully understand the potential movement of the rodenticide into, and degradation from, the ecosystem.
A “one time” treatment of the occurred in the fall 2008 with a bait containing the brodifacoum to remove introduced Norway rats. The purpose of the removal was to restore native seabirds and to heal the ecosystem after more than 200 years of predation by non-native rats that arrived by shipwreck in the late 18th century. If the rats have been successfully removed, there will be no need to re-treat the in the future. No living rats have been detected on the island, and the Service and its partners are cautiously optimistic that all of the rodents have been eradicated. If another year passes without a rat sighting, the team can declare the rat-free for the first time in 229 years. Early signs of positive ecosystem change were documented; nests and chicks of black oystercatchers, glaucous-winged gulls, and common eiders were observed, in addition to a first-time record of breeding seabirds on an offshore rock previously inhabited by rats. Reports from the camp indicate that all bird species on the except eagles are present in numbers similar to those found during pre-treatment surveys. Falcons and gulls were observed successfully nesting on the island, and several observations of live adult and sub-adult eagles were made. Species such as murrelets, storm-petrels and puffins are expected to recolonize the in the coming years if the rat eradication is proven successful A survey team dispatched to the this May encountered a higher-than-expected number of carcasses of two non-target species. Biologists found 213 glaucous-winged gulls and 43 bald eagles. The team of biologists has reported no evidence of ongoing mortality on the island. The Service has no evidence that new mortalities have occurred. The partnership intends to dispatch a second team in early August to continue monitoring on the island.###
