Baiting teams use a boat to access the difficult coastal clefts of Little Bense Island.
An important step in restoring the islands’ ecosystems was the removal of the invasive mammal species that were introduced in the late 1800s. Rats (Rattus norvegicus), mice (Mus musculus), and European rabbits (Oryctolagus cuniculus) were eradicated in August 2016 using the standard techniques developed in New Zealand and now practiced worldwide in the fight against invasive pests. The operation involved the dispersal of cereal pellets laced with a common rodenticide, brodifacoum. The baits were hand-cast along the coasts of Bense and Little Bense, and also along transects across the interior of the islands. The key to a successful operation is to ensure every rodent has access to the poisoned pellets within the range in which it normally moves. Rats have relatively large home-ranges and are therefore are easy to “cater” to, but mice present a more difficult problem. Mice have very restricted home-ranges, so bait transects on Bense and Little Bense Islands were only 20m apart to ensure each mouse encountered a pellet on its nightly foraging trips. (On rat-only islands, the transects are usually 50m apart.) Bense and Little Bense Islands are the first in the Falklands to be cleared of mice, the first to be cleared of rabbits, and the first where three pest species were eradicated in one operation.
For a detailed look at this eradication operation, please see our paper: Carey, P.W. 2018. Simultaneous rat, mouse and rabbit eradication on Bense and Little Bense Islands, Falkland Islands, pp. 108–113 In: C.R. Veitch, M.N. Clout, A.R. Martin, J.C. Russell and C.J. West (eds.) (2018). Island Invasives: Scaling up to Meet the Challenge. Gland, Switzerland: IUCN. Download the PDF here.
Bait is broadcast by hand along very specific transects.
Acknowledgements
SAFER is grateful to the following who were very helpful in our successful removal of introduced pests:
Thanks to the Falkland Islands government for the generous donation of bait. Andy Cox, Sally Poncet, Elaine Murphy, and Keith Springer all shared their vast pest eradication experience and advised on operational design. For logistics support we thank UK Ministry of Defense / British Forces South Atlantic Islands, Bill & Shirley Pole-Evans, Kay McCallum, Lindblad Expeditions, Hurtigruten Cruises, and One Ocean Expeditions. Paul Goodhue created the excellent operational maps for baiting that were critical to our success. And we also thank N. Beazley, Encounter Foundation of New Zealand, J. & S. Holman, Environmental Planning Department of the Falklands government, Falklands Conservation, G. Roldan, and the Baroness Hooper CMG for their support. For the hard work spreading the bait we thank to S. Henry, S. Cleminson, J. Henry, T. Poole, L. Hartnoll, and D. Hewitt.
