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Feral Cats Eradicated, Mice Now Devour Bird Nests
30 Sep
Summary
- Feral cats, introduced to control mice, decimated seabird populations.
- Cat eradication efforts on Marion Island took decades to complete.
- Mice, not cats, now pose the biggest threat to recovering seabird numbers.
In 1949, five cats were introduced to sub-Antarctic Marion Island to control a burgeoning mouse population. This measure created a new ecological crisis: a feral cat population that devastated native seabirds. By 1977, their numbers swelled to thousands, leading to an estimated 450,000 seabirds killed annually, drastically reducing petrel populations.
A multi-faceted eradication program, combining virus introduction, hunting, and trapping, was implemented over many years. Researchers documented the evolving strategies required to combat the resilient cat population. The intensive efforts, involving thousands of hunting hours, finally succeeded in eradicating the cats by 1991.
Following the cats' removal, scientists surveyed the island in 2013 to assess seabird recovery. While burrowing petrel numbers increased by 56% since 1979, the recovery was less dramatic than anticipated. Researchers identified the continued presence and predation of house mice as the primary reason for the limited return of seabird populations to their previous levels.
