Invasive mice eat Albatrosses live on a remote island in the Indian Ocean, so environmentalists have come up with an explosive solution: “bombing” the mice.
Mice have been wreaking havoc on Marion Island between South Africa and Antarctica for decades. Humans accidentally introduced the mice in the 19th century, and since then the rodents have developed a taste for wandering albatrosses (Diomedea exulans) and other endangered seabirds.
The Mouse-Free Marion Project, a collaboration between the South African government and BirdLife South Africa, is seeking to raise $29 million to drop 660 tonnes (600 metric tonnes) of rodenticide-laced pellets on the island in winter 2027. News agency AFP was reported on Saturday (24 August).
The project involves sending a helicopter group to drop the pellets. By attacking in winter, when the mice are hungriest, conservationists hope to wipe out the entire mouse population of up to 1 million people.
“We have to get rid of every single mouse,” Mark AndersonCEO of BirdLife South Africa, told AFP news agency. “If a male and a female were left, they could mate and eventually return to where we are now.”
Related: On a third remote island, adult albatrosses are found gnawed to death by mice
House mice (Mus musculus) first arrived on Marion Island with sealers. They began their reign of terror by decimating the island's invertebrates and feasting on seabird eggs. By 2003, the mice had Eating seabird chicks aliveand now, a decade later, mice have discovered that they can compete with adult animals.
Researchers discovered the Carcasses of eight adult migratory animals Albatrosses in April 2023. The birds had deep wounds on their elbows consistent with mouse attacks and probably died from secondary infection or starvation. Since then, further reports of deaths in adult seabirds indicate that mouse attacks are increasing.
“Mice just climb on them and slowly eat them until they succumb,” Anderson said. “We lose hundreds of thousands of seabirds every year because of mice.”
Albatrosses are defenseless against mice because they did not co-evolve with terrestrial predators. They spend most of their lives at sea, and nesting sites like Marion Island are so isolated that mice and other non-marine mammals could not reach them until humans arrived. Because the birds evolved to live in an environment where they did not encounter terrestrial predators, they have no mechanisms to defend themselves.
An earlier attempt to use cats to control the invasive mouse population on Marion Island had disastrous results. Researchers brought five cats to the island's weather station in 1948, but the cats' offspring became feral and preyed on seabirds and mice.
The wild cats multiplied and spread across the island until they An estimated 455,000 birds were killed a year in the 1970s. Researchers successfully eradicated the cats in 1991.
The rodenticide at the heart of the new eradication strategy should only kill mice because Marion Island's native invertebrates are unaffected and seabirds normally feed at sea.
