Conservation experts announced plans on August 24 to drop tons of rodenticide pellets on a remote island to eradicate rats that prey on seabirds, including the endangered wandering albatross and many other seabird species.
The rat population, which feeds on the eggs of some of the world’s most critical seabird species nesting on Marion Island—located about 2,000 km southeast of Cape Town—has begun to eat live birds, according to conservation expert Mark Anderson. Among these is the wandering albatross, with a quarter of the species nesting on the island in the Indian Ocean.
An albatross being preyed upon by rats on Marion Island. (Photo: Michelle Risi)
“For the first time last year, we discovered rats attacking adult wandering albatrosses,” Anderson shared during a meeting with BirdLife South Africa, the leading bird conservation organization in South Africa. Researchers had photographed birds with bloodied bodies, some with flesh gnawed from their heads by the rats.
Among the 29 seabird species breeding on the island, 19 are locally endangered, according to the Mouse-Free Marion Project. Incidents of rat attacks have surged in recent years, but seabirds do not know how to respond, as they evolved in an environment devoid of predators on the island, Anderson noted, who leads the project and serves as the executive director of BirdLife South Africa. “Rats simply climb onto the birds and slowly eat them until the victim dies. This can take several days. We lose hundreds of thousands of seabirds each year due to rats,” Anderson explained.
As one of the most critical bird conservation efforts globally, the Mouse-Free Marion Project has raised a quarter of the $29 million needed to deploy a helicopter team that will drop 600 tons of rodenticide pellets on the rugged island. They aim to drop the pellets in the winter of 2027 when the rats are hungriest and the breeding seabirds are mostly absent. Pilots will have to fly in harsh conditions across every nook and cranny of the island, which is approximately 25 km long and 17 km wide. “We must eliminate every rat. If even one male and one female remain, they can breed and repopulate,” Anderson stated.
The rat population on Marion Island has proliferated due to warmer temperatures from climate change, leading to more frequent and longer breeding periods. After consuming all available vegetation and invertebrates, the rats have turned their attention to seabirds. House mice arrived on the island in the early 19th century, and around 1948, five cats were introduced to control their numbers. However, the cat population ballooned to about 2,000, killing approximately 450,000 birds annually. A project to eradicate the cats was finally completed in 1991.
