An 18-strong international team is hard at work in South Georgia, undertaking the final phase of the world's largest rodent eradication project, run by the South Georgia Heritage Trust. Known collectively as ‘Team Rat’, its departure for South Georgia in January coincided with the discovery of a nest of five South Georgia pipit chicks (Fig. 1) in an area overrun with rats before being baited by the trust in 2013. The pipit is the world's most southerly songbird.

Fig. 1. South Georgia pipit nest. Photo Sally Poncet.

The South Georgia pipit is endemic to South Georgia, with an estimated 3000 pairs nesting on the island. It has an IUCN status of Near Threatened. Previous to the baiting work it bred only on offshore islands and areas of the southern coastline inaccessible to rats. In stark contrast, Rattus norvegicus has been thriving ever since it first reached the island as a stowaway on sealing vessels in the late 1800’s. All of the small ground-nesting birds on the island, such as the pipits, prions and petrels, have had their nests decimated by the interloper, whose numbers are unknown but were reckoned to be in the millions before the baiting work began.

Rat populations range along the north coast of South Georgia. Their DNA varies from place to place, evidence that populations have been kept separate over the years by South Georgia's glacial divides. The same barriers have halted the rats’ progress to areas on the south coast, and have allowed ‘Team Rat’ to bait the island over a number of years, confident that these natural boundaries will stop any re-invasion from neighbouring areas. However with glacial recession rats have been able to penetrate ever further into the pipits’ territory. Even offshore islands are under threat of invasion from rodents given the right conditions (favourable currents and floating debris). The only way of ensuring the survival of the South Georgia pipit as a species is through the goal of eliminating every rat from South Georgia.

The discovery of the first pipit nest in an area cleared of rodents, was made at Schlieper Bay near Weddell Point to the very northwest of the island. The nest was found by Sally Poncet, an expert on South Georgia wildlife. Poncet was a member of Team Rat during its Phase 1 operation. She discovered the nest while on an expedition to survey wandering albatrosses. Many others have now reported pipits in numbers in the areas treated in 2013.

Experts estimate that the seabird population on South Georgia could increase by as much as 100 million in the absence of rodents.