On 14 June 2021, the Anguilla National Trust (ANT), in collaboration with Fauna & Flora International (FFI); New Zealand-based Wildlife International Management Ltd. (WMIL); and independent island restoration experts, launched an intensive and logistically-difficult initiative to remove mice from Sombrero Island. Led by Mr. John Tayton and Mr. Toby Ross, a team of Anguillian residents spent two months removing invasive mice from Sombrero Island Marine Park Nature Reserve – Anguilla’s furthest offshore cay that is also internationally-recognised as a Ramsar Site and an Important Bird and Biodiversity Area. It is also home of the Critically Endangered Sombrero ground lizard, a black lizard found on Sombrero Island and nowhere else in the world.
The mouse eradication operation involved positioning 940 temporary bait stations. Interspersed amongst the bait stations were 1880 monitoring points. Bait and a combination of non-toxic wax monitoring, soap, chocolate resin, trail cameras, mouse tracking pads, and chew cards, were checked daily for signs of mice. Although baiting and monitoring took place over a period of eight weeks, to ensure that every mouse was targeted and removed, there were no signs of mice 22 days after the beginning of the baiting period. While project partners had initially thought that mice would only be found around the Sombrero lighthouse, and within the more vegetated parts of the island, surprisingly, signs of mice had also been observed and recorded on the far northern and southern ends of the island where there was no vegetation.
Following international practice, the cays will be routinely monitored by ANT staff and volunteers for any signs of mice over the next year. Eradication team leaders will return to Anguilla next year to conduct an intensive final check of the island for signs of mice before the island will be officially declared mouse-free. Biosecurity monitoring of the offshore cay, however, will continue indefinitely by the ANT to ensure that mice do not reinvade the island.
Sombrero Island represents the fourth island that the ANT and partners have restored. Black rats were successfully removed from Dog Island in 2012, and brown rats were removed from Prickly Pear East and Prickly Pear West in 2018. The ANT would like remind members of the public that everyone has a role in ensuring that Anguilla’s offshore cays remain rodent-free by ensuring that rats and mice are not inadvertently brought to any of the islands as stowaways on their boat, in their bags, boxes, or containers. If a rat or mouse is found on a vessel headed to the cays, the animal should not be thrown overboard alive: rodents are excellent swimmers and can easily swim to shore. Any sightings of rats or mice on Dog Island, the Prickly Pear cays, or Sombrero Island, should be immediately reported to the Anguilla National Trust by calling 497 5297 or 235 5297.
This island restoration initiative is part of a larger three-year project that began in 2019. This project aims to increase the resiliency of Anguilla’s biodiversity – and especially the island’s endangered species to climate change, and other threats, as well as to enhance the management of Anguilla’s Marine Park. The project is funded by the UK-based Darwin Plus grant mechanism, the Prince of Wales Charitable Foundation, the John Ellerman Foundation, the Betty Liebert Trust, FFI’s Species Fund, and the US Fish and Wildlife Service’s Neo-Tropical Migratory Bird Conservation Act. The larger project is being implemented in collaboration with the Fisheries and Marine Resource Unit-Department of Natural Resources and FFI.
The Sombrero Island mouse eradication would not have been possible without the on-the-ground assistance provided by the eradication team co-leaders, Mr. Tayton and Mr. Ross, as well as the technical expertise provided by Ms Biz Bell and Mr. Kelvin Floyd of WMIL, Dr. Jenny Daltry of Re:Wild, and Mr. Olivier Raynaud of FFI. The ANT also recognises the assistance provided by the Anguilla-based mouse eradication team, Calypso Charters, Good Living Charters, Open Seas Charters, Ashley & Sons, the Agricultural Unit-Department of Natural Resources, and Syngenta which donated the bait.
For more information about Sombrero Island Marine Park Nature Reserve, the cay’s biodiversity, the mouse eradication initiative, or any work of the Anguilla National Trust, please contact the Trust at 235 5297 or antadmin@anguillanet.com.
– Press Release
