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SGHT Habitat Restoration Project


Eradicating invasive rodents from South Georgia

 

 

Watch footage above of the Phase 1 fieldwork showing the preparations in the Falkland Islands, the helicopters flying on and off One Ocean Expeditions' cruise ship the Marina Svetaeva, and the field team carrying out the work to clear the first four areas of South Georgia of invasive rodents. Thank you to GEO for providing the footage and to Emile Shemilt and Paul Shafi for their help with the footage.

(Note there may be a delay while the footage is downloaded).

 

Rats occur throughout almost all of the hospitable, warmer areas of the island – the same habitat required by native wildlife. Mice are only known to occur in one area in the northwest of South Georgia; however, recent reports have raised concerns that they may have been introduced recently into new areas.

Based on experience gained around the world, the only feasible way to eradicate all rodents on an island the size of South Georgia is to spread toxic bait by helicopter. This technique has proven to be effective in eradicating rodents from smaller islands and is now widely used. However, this will be an immense undertaking – at 100,000 hectares in size, the area of South Georgia to be cleared is more than eight times larger than Campbell Island (New Zealand), which at 11,300 hectares is the largest island ever cleared of rodents until now. However, as South Georgia’s rodent population is divided into a number of independent units by the island’s sea-level glaciers, eradication of all rodents is feasible. The eradication operation on South Georgia will require three helicopters, approximately 300 tonnes of rodent bait and three seasons to complete the work.

Experience from other rodent eradication operations has demonstrated that the bait pellets to be used on South Georgia are extremely attractive to rodents; they will eat them in preference to their natural food. The active ingredient in the rodent bait pellets is called brodifacoum. It is an anti-coagulant, which causes the rodent to die of internal bleeding and organ failure. All rodent baits that can offer 100% success act in a similar way to brodifacoum – none offer a more humane solution to this problem. Suffering by any animal is deeply regrettable, but unless rodents are removed from South Georgia, every year thousands, perhaps millions, of young birds will be eaten alive by rats. The death of one rat now will prevent the killing of many nestlings over time, and probably save one bird, the South Georgia Pipit, from extinction. On balance, most people would agree that eradicating rodents from the South Georgia is justifiable, indeed necessary.

<Read more about the project's background and view the planning documents>

 

Monitoring during operations

Every precaution is being taken to minimise the risk to native and endemic fauna. The majority of the birds on South Georgia are seabirds that eat only marine prey; therefore, it is unlikely that they will consume the poison. Scavengers, such as skuas and giant petrels, could ingest enough poison through eating dead or dying rats to become ill themselves. However, rodents that take the bait become photophobic (scared of light) and consequently most die in their burrows, where they are inaccessible. Therefore, death of scavengers due to secondary poisoning is likely to be relatively rare. Streams and drinking water will not be affected because brodifacoum is not soluble in water. A few birds, such as ducks and gulls, might be tempted to eat the pellets directly. The habitat restoration team will carefully monitor each season’s operation, and will be ready to modify or stop work altogether if any wildlife looks likely to suffer long-term, population-level damage as a consequence of the Project.

The team is also working to ensure that the operations using helicopters do not scare the wildlife. Helicopters will approach any bird colonies slowly at a high enough altitude to minimise impact and only go near them when actually spreading bait in their vicinity. Seals are more tolerant than birds to disturbance, but every effort will be taken minimise their stress wherever possible. In all cases, observers on the ground will monitor for any impact caused by the helicopters and procedures will be modified if needed. <Answers to frequently asked questions about the SGHT Habitat Restoration Project> 

Phase 2 complete!

Years of planning and fundraising went into preparing for the first phase of the Project – the eradication of rodents from areas around and adjacent to King Edward Point and Grytviken, from a rocky promontory on the western side of Mercer Bay (green zone on map, below), and from the recently infested Saddle Island. While the Phase 1 area was approximately one tenth of the total infested area of South Georgia, it was substantially larger than Campbell Island, the largest island cleared before the South Georgia project.

With plans for Phase 1 complete, SGHT assembled its habitat restoration team, 'Team Rat', which brought together experts in invasive species eradication as well as team members with extensive experience of working in South Georgia. Permission was granted by the Government for South Georgia and the South Sandwich Islands (GSGSSI) to begin fieldwork in February/March 2011. The much larger second Phase was then carried out with a team of 25 from February to May 2013. The operational work was a complete success with the team enduring some of the harshest weather on South Georgia for a decade. If the area baited (65% of the infested parts of the island) has indeed been completely cleared of rodents, the island's birds will be able to nest safely for the first time in over two centuries. Signs are good that birds are returning to the areas cleared in Phase 1, and two years on there is no sign of rats.   

Phase 1 cost about £1.6 million, Phase 2 (which cleared an area five times the size of Phase 1) cost £3 million. SGHT is grateful to all those donors who contributed to funding for the first two phases of the SGHT Habitat Restoration Project. <List of SGHT donors who have contributed to the SGHT Habitat Restoration Project> 

 

The future of the SGHT Habitat Restoration Project

We now urgently require funding for Phase 3, the eradication of rodents from the remainder of South Georgia by 2015 (red zones on map). A further £3 million (US$5 million) is needed to complete the work.

Ultimately, the whole of South Georgia will be overrun by rats and mice unless every single rodent is eradicated, and soon. Our objective is clear – we must remove every rodent from every piece of land on South Georgia, and leave it rodent-free for generations to come. <Read more about South Georgia’s potential for recovery following completion of the SGHT Habitat Restoration Project> 

Your support for SGHT can directly help return millions of seabirds to South Georgia, and restore the island’s native ecology. Join the donors who are helping to make this happen. <Learn how you can support the SGHT Habitat Restoration Project>

The arrival of rats on South Georgia as stowaways on sealer and whaler ships had a catastropic effect on the island's bird populations. The SGHT Habitat Restoration Project aims to remove every rodent from every piece of land on South Georgia by 2015, helping to restore its native ecology and restore millions of seabirds to the island. <More information about South Georgia's endemic and native species that are threatened by invasive rodents>