Off the coast of Mauritius lies a series of small, mostly uninhabited, islands that once told a very different story than they do today. For decades, animals brought there by ship, including mice, cats, goats and rabbits, have quietly decimated native plants and pushed seabird colonies to the brink of collapse.
Then, starting in the late 1970s, conservationists and the government of Mauritius began long and painstaking efforts to remove this invasive species from islands such as Round Island, Ile aux Aigrettes, and Gunner’s Quoin. It took decades of careful work, but the results speak for themselves. Seabirds that had nearly disappeared from these shores are now nesting again, and local forests are slowly reclaiming land they lost more than a century ago.
Why invasive species have pushed Mauritius’ seabirds over the edge
Mauritius has no native land mammals except bats, so when sailors and settlers introduced rats, goats, rabbits and cats over the centuries, the local wildlife had no defenses against them. Rats in particular prove devastating to seabirds, as they raid their nests and eat eggs and chicks long before the young birds have a chance to develop. According to a government report by the Mauritius National Parks and Conservation Service, invasive alien species remain the greatest threat to the country’s native biodiversity, and this combination of introduced predators has pushed many seabird populations to the brink across small offshore islands.
The long battle to save Round Island
Round Island, a small volcanic island located about 22 kilometers north of the mainland, has become one of the country’s oldest and most important restoration efforts. For more than 150 years, introduced goats and rabbits have stripped the island of its vegetation, causing severe soil erosion and wiping out large portions of the local plant life. Working with the Durrell Wildlife Conservation Trust, conservationists removed the goats by 1979 and finally eliminated the rabbits by 1986, according to the Mauritius Wildlife Foundation. Once these grazing animals were gone, the island’s palm forests slowly began to recover, and with them came a veritable revival of the local reptiles and seabirds that depend on this habitat to breed.
Disinfection of mice and cats from Ile aux Aigrettes
A similar transformation has occurred on Ile aux Igret, a small atoll off the southeast coast of Mauritius. Since the 1980s, teams have worked steadily to remove mice, cats, and invasive plants from the island, finally eradicating these major predators by the early 2000s. With this threat gone, seabirds have begun to successfully return to their nests, including species such as the white-tailed tropicbird and the wedge-billed shearling, both of which have suffered for years under constant predation.
The island’s plants also responded well when rats were no longer around to damage seeds and young plants, allowing the original forest cover to slowly rebuild itself.
Clear the northern islands one by one
Apart from Round Island and Ile aux Aigrettes, Mauritius also addressed a group of small northern islands through a multi-year coordinated programme. Norway rats and hares were removed from Gunner’s Quoin, ship rats were purged from Gabriel Island, and rats were eradicated from Ile aux Cocos and Ile aux Sables, with additional cats and rodents later removed from Flat Island as well.
These eradication operations, carried out by wildlife management specialists working with the Mauritian government, were slow and methodical, often involving specially designed bait stations placed throughout entire islands to ensure that no invasive predators survived the operation.
Seabirds are slowly returning to their old nesting places
The gains from all this work have been steady rather than immediate, but seabird numbers on these islands have really risen as the threat from predators has disappeared.
Species such as the wedge shearling and the red-tailed and white-tailed tropicbird have re-established nesting colonies on islands where they had previously been completely driven out, taking advantage of the restored vegetation and predator-free land to breed safely again.
Reptile populations on these islands have also benefited, with many rare endemic species now able to survive and even be reintroduced to islands where they had previously disappeared.
The conservation model is still used today
What makes this story stand out is not just the outcome, but the approach behind it. Restoring these islands will require sustained collaboration between the Government of Mauritius, the Mauritius Wildlife Foundation, the Durrell Wildlife Conservation Trust, and the country’s Forest Service, over several decades rather than one quick fix. The same island restoration model continues today across nearly a dozen offshore islands, and has become a reference point for conservationists working on similar rewilding projects elsewhere in the world.
While invasive species such as monkeys remain an ongoing challenge on mainland Mauritius, the country’s offshore islands now stand as a true example of what patient, well-coordinated conservation work can achieve for species that were once on the verge of extinction. Removing goats from Round Island in 1979 and watching palm forests slowly return over the following decades is a story of conservation measured in the right units: not years but generations of plants, not headlines but a steady accumulation of nesting seabirds. The work was unattractive, systematic, spread over half a century, and precisely for this reason it succeeded in ways that faster interventions rarely do.
