In alaska, where the majority of the U.S. S breeding seabirds and nearly half of its shorebirds reside, the impact of invasive rodents is particularly severe

This Project Grant award from the U.S. Fish and Wildlife Service under the Fish and Aquatic Conservation - Aquatic Invasive Species program (CFDA 15.608) aims to validate aerial baiting and non-target species mitigation strategies for eradicating invasive Norway rats from Great Sitkin Island in the Alaska Maritime National Wildlife Refuge. The $835,696 award will fund field trials to determine optimal bait application rates, map rat distributions, and test bait application methods to minimize impacts on sensitive habitats and salmon. The project will also conduct surveys and test attractant methods to mitigate non-target impacts on avian scavengers. Additionally, a subaward will investigate rodenticide trophic transfer to understand potential impacts on salmon and their predators. The project seeks to build collaboration with local Alaskan communities, regulatory agencies, and stakeholders, with the insights gained serving to advance future rat eradication efforts across the Aleutian Islands. The award period is from October 1, 2024 to September 30, 2026.

The alaska maritime national wildlife refuge (amnwr) has been making great strides in eradicating invasive species from the aleutian islands for over 70 years. With the successful eradication of foxes from amnwr islands now complete, the focus has shifted to rats. In partnership with the U.S. Fish and wildlife service, U.S. Department of agriculture, animal and plant health inspection service, wildlife services, and USDA national wildlife research center (nwrc), island conservation aims to validate aerial baiting and non-target species mitigation strategies essential for eradicating invasive norway rats (rattus norvegicus) from great sitkin island within amnwr. Leveraging lessons learned from the 2008 successful removal of norway rats from hawadax (RAT) island in amnwr, this endeavor builds upon previous experiences to ensure effective RAT eradication on great sitkin. Within a decade of RAT removal, significant increases were observed at hawadax in several terrestrial and marine bird species, including graycrowned rosy-finch, song sparrow, pacific wren, snow bunting, black oystercatcher, glaucouswinged gull, and tufted puffin (croll ET AL., 2016). Nests of three bird species not recorded as breeding on the island were seen: song sparrow, tufted puffin, and rock sandpiper. Also, breeding-associated vocalizations of leachs storm-petrel, not previously documented, were detected. Bald eagle and glaucouswinged gull populations surpassed pre-eradication levels, underscoring the fact that the long-term benefits of RAT eradication outweigh short-term impacts of rodenticide on non-target species and the environment. This project will conduct field trials to determine optimal RAT bait application rates across different habitats, determine the upper distributional range (including snow-covered elevations) of rats to devise treatment strategies, and trial various bait application methods around freshwater streams and sensitive habitats to minimize impacts to anadromous salmon. Raptor experts will lead formalized surveys and test attractant methods for avian scavengers to mitigate non-target impacts. A subaward will contract nwrc to investigate patterns of rodenticide trophic transfer to better understand potential impacts on salmon and salmon predators. The project aims to build collaboration between local alaskan native communities, regulatory agencies, and other stakeholders by hosting an in-person workshop and virtual events. The insights gained on great sitkin will be pivotal in advancing RAT eradication efforts and align with amnwr s overarching vision of a RAT-free aleutian islands . Success on great sitkin will catalyze restoration efforts throughout the aleutian archipelago, extending to kiska, amchitka, and attu islands, where populations of burrow and crevice nesting seabirds, as well as entire ecosystems, face imminent threat from RAT infestation. Insights gained from this research will increase the effectiveness of eradication tools and methods on these additional islands where future RAT eradication scoping and compliance is underway.