Escalating threats: house mouse attacks on adult wandering albatrosses spread across Marion Island
摘要
Invasive rodents severely impact native species, especially on oceanic islands. House mice Mus musculus are known predators of seabird chicks, and there is growing concern about their attacks on adult birds. On sub-Antarctic Marion Island, the single largest breeding site for wandering albatrosses Diomedea exulans, invasive mice, the sole introduced mammal, pose an escalating threat to this Vulnerable species. We report the first direct evidence of mice attacking adult wandering albatrosses, and record mouse attacks on adult wandering albatrosses beyond the localised incidents reported in 2023. Of 2,979 wandering albatross nests counted island-wide in January 2024, 2,295 remained active in April, with 1,102 attended by adults brooding or guarding chicks. Of these, 11 adults (1%) exhibited mouse-inflicted wounds (including a scalp injury, as well as the more common wing joint wounds), and two fresh adult carcasses were discovered. Injured adults and carcasses were distributed across all wandering albatross breeding colonies. Wounds predominantly affected males (10 of 11); one adult succumbed to its injuries within six weeks. The 11 nests with injured adults had a 45% breeding success rate, below the island-wide average of 61%. At Cape Davis, where mice were first recorded attacking adults in 2023, breeding success was just 28%. This expansion in attack range and severity underscores the urgent need to eradicate mice from Marion Island to conserve wandering albatrosses and other threatened biota.