Island's Mice Now Target After Cat Eradication Success

South Africa established a meteorological station on Marion Island in 1948, where cats were introduced to control house mice. This measure inadvertently created a new ecological problem, with the cat population rapidly expanding from five to over 2,000 by 1975.

By the mid-1970s, these feral cats were estimated to kill approximately 450,000 seabirds annually, devastating local bird populations, particularly burrowing petrels. Some species were even extirpated from the island due to this intense predation.

An extensive eradication effort, beginning in 1977 with a virus and later including hunting, trapping, and poisoning, eventually succeeded. The last cat was shot in January 1991, and the island was declared cat-free by 2000.

Despite the cats' removal, invasive house mice remain a significant conservation challenge. A "Mouse-Free Marion Project" is preparing for a large-scale eradication, with an aerial baiting trial scheduled for April-May 2027.