Mice attacks on Midway albatrosses are spreading but plans are afoot to eradicate them

ACAP Latest News has previously reported that introduced House Mice Mus musculus on Sand Island, part of the USA’s Midway Atoll in the North Pacific, had taken to attacking Laysan Phoebastria immutabilis and Black-footed P. nigripes Albatrosses in the 2015/16 breeding season, resulting in a number of mortalities (click here).

Mouse attacks on Midway albatrosses during the 2015/16 breeding season, photographs by US Fish and Wildlife Service and Robert Taylor

News is now in for the latest (2016/17) breeding season that mice attacks on albatrosses are continuing and are spreading over more of the island - as extracts below taken from a blog show.

Areas where albatrosses have been attacked by mice on Sand Island, Midway Atoll National Wildlife Refuge as of 15 January 2017.  Areas with green borders indicate areas where only abandoned nests were found but no bitten or dead birds.  Red triangles represent individual dead or bitten birds 

“On December 4, while out checking birds in areas where mice had attacked the previous year, [U.S.] Fish and Wildlife Service biologist Meg Duhr-Schultz found several bitten birds, removing any possibility that the events of 2015/2016 were some kind of El Niño-driven anomaly. Staff and volunteers were deployed over the next few days to survey other parts of the island and more attacks were discovered. In less than a week the area impacted by mouse attacks had exceeded the total area affected during all of the previous year. And the fact that the mouse attacks were noticed several weeks earlier was of real concern.  Again, the Fish and Wildlife Service had to quickly figure out what to do and the decision was made to take steps to reduce the mice populations in the affected areas.  So far the actions that the Fish and Wildlife have taken seem to be having a positive effect. The abundance of mice in the impacted area dropped sharply in areas where rodenticide was applied [by hand].”

“Over 1200 bitten birds have been discovered, 211 of which have died.  Nearly one thousand abandoned nests have been documented. Mice may also be having impacts on other seabirds here but it would be more difficult to detect, especially for the burrow-nesting species.”

“As the only atoll within the Papahānaumokuākea Marine National Monument that still harbors lingering populations of invasive rodents, there have been plans to eradicate mice from Midway Atoll for some time.  The discovery that mice are harming the albatrosses should only strengthen the case for their removal and expedite the [eradication] project’s implementation.  First steps were, in fact, taken just last November when a team of biologists and invasive species experts from the Fish and Wildlife Service and the non-profit organization Island Conservation visited Midway [to] begin a study of the project’s feasibility.”

A dead Laysan Albatross found during the attacks of 2016/2017 next to an abandoned nest; photograph by Robert Taylor

John Cooper, ACAP Information Officer, 23 January 2016