Above picture: The bait-spreading bucket is lowered to the ground to be reloaded with cereal bait; photograph by Lucie Pichot

As the Mouse-Free Marion (MFM) Project continues to work towards its 2027 target of eradicating the island’s seabird-killing House Mice Mus musculus, heartening news for the project team and supporters comes from France’s sub-Antarctic Amsterdam Island, 3384 km away in the southern Indian Ocean.  The project RECI (Restauration des écosystèmes insulaires de l’océan Indien; Restoration of Insular Ecosystems of the Indian Ocean) has announced the completion of the baiting operation to eradicate Norway Rats Rattus norvegicus and House Mice.

The bait-spreading bucket is suspended below the helicopter on a long cable; photograph by Lucie Pichot

The first baiting application took place over 7-25 June 2024, dropping rodenticide-laced cereal bait over the 5800 ha island, including along the Entrecasteaux cliffs, utilizing a bait-spreading bucket suspended below a single-engine Airbus A350 B3 helicopter, known as a Squirrel.  The helicopter was operated by a team from the Réunion-based company Helilagon.  In addition, rodenticide bait was spread by hand around the Martin-de-Viviès scientific station, with the baiting of interiors, inside ceilings and underneath buildings and field huts.

To guarantee access to bait for all the island’s rats and mice, including any young rodents not weaned at the time of the first application, a second bait treatment commenced on 5 July and was completed on 23 July.  A second manual treatment of the station buildings was also carried out during this time.

Setting up a camera trap to detect rodents on Amsterdam; photograph by Lucie Pichot

During and on completion of the eradication operation the RECI team was also involved with:

  • placement of biosecurity bait and monitoring stations,
  • deploying camera traps;
  • controlling alternative food resources;
  • monitoring bait availability by the establishment of quadrats distributed over the island; and
  • dismantling and cleaning up the load sites.

The RECI and Helilagon teams gather after the completion of the eradication operation; photograph by Lucie Pichot

The eradication team and all the TAAF and Helilagon equipment were retrieved on 19 August after four months on the island by the French Antarctic vessel Marion Dufresne during a five-day visit.  Two field assistants have stayed on the island to set up a biosecurity detection network and to monitor camera traps around the island for signs of any surviving rodents.  Fabrice le Bouard, Restauration des écosystèmes insulaires de l’océan Indien, has informed MFM News that so far the signs are promising, with no live rodents being detected on the island in the first couple of weeks after the eradication attempt.  However, as is standard practice, a two-year period with no signs of rodents is required before Amsterdam can be declared free of its rats and mice.

Marion is five times larger than Amsterdam, so the Mouse-Free Marion Project will be a much larger operation. requiring more personnel, equipment and bait.  However, the project team is “up for it” and is continuing to put in the necessary hard work to achieve its goal of an island declared free of its only remaining introduced mammal before the decade is out.

Information from Fabrice le Bouard of RECI and the Facebook page of Terres australes et antarctiques françaises (TAAF).  Photographs by Lucie Pichot, TAAF.

John Cooper, News Correspondent, Mouse-Free Marion Project, 17 September 2024

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A Grey-headed Albatross stands over its chick on Marion Island; photograph and poster design by Michelle Risi. See many more freely downloadable Mouse-Free Marion Project posters here

The Mouse-Free Marion Project is a registered non-profit company (No. 2020/922433/08) in South Africa, established to eradicate the invasive albatross-killing mice on Marion Island in the Southern Ocean.  The project was initiated by BirdLife South Africa and the South African Department of Forestry, Fisheries and the Environment.  Upon successful completion, the project will restore the critical breeding habitat of over two million seabirds, many globally threatened, and improve the island’s resilience to a warming climate.  For more information or to support the project please visit mousefreemarion.org.