Millions of rats to be killed to protect rare South Georgia birds

The threatened South Georgia pipit. Credit SGHT

March 2010. Introduced alien species are a major cause of the loss of native biological diversity worldwide, and their impacts are especially severe on island ecosystems. On South Georgia, the introduction and spread of Norway rats has been highlighted as the greatest threat to the environment of the island today.

It is estimated that there are several million rats on South Georgia and they prey on the many sea bird colonies, their eggs and chicks, on the island. A few colonies of the rarest birds are protected by glaciers, but as the world warms and the glaciers retreat, the last few protected colonies are under threat.

Habitat Restoration Project
The objective of the South Georgia Heritage Trust (SGHT) Habitat Restoration Project is to remove rats from the entire island of South Georgia with a view to restoring South Georgia to its earlier status as one of the most important seabird islands in the world. Failure to clear South Georgia of rats will result in a further decline in bird numbers because climate change is reducing the effectiveness of glaciers as barriers to the spread of rats. Consequently, the few areas currently free of rats are expected to be overrun unless action is taken soon.

South Georgia pintail. Credit SGHT

Poison bait drops
Helicopters will be used to distribute bait drops of the second generation anticoagulant toxin brodifacoum in cereal-based pellets. It is proposed that the operation is undertaken in two phases. The first (trial) phase, scheduled to take place in February-March 2011, will be followed by monitoring to ensure the complete eradication of rats, assess the effects of bait on non-target species and assist in the optimisation of logistics and operational procedures for the remainder of the project in the challenging conditions of South Georgia.

A total of 18 discrete baiting zones will be cleared of rats separately during the 2011 trial phase and subsequent phase II operations (2012-14). In addition to monitoring at the end of each baiting season, further monitoring will be carried out throughout the island in 2015 and 2016 in order to ensure that no rats have survived.

South Georgia pipit
The primary outcomes of the proposed operation will be to save the native South Georgia pipit from extinction, and increase the numbers of breeding birds on the island by millions.

South Georgia Habitat Restoration Project Director, Professor Tony Martin has been appointed Professor of Animal Conservation at the University of Dundee. Tony is a zoologist who has lived and worked on South Georgia, and who has organised several large logistical operations overseas in remote areas, including the renewal of the Bird Island base for BAS. Tony is also an expert on the South Georgia Pintail and keeps a flock of the ducks at his farm in Cambridgeshire.

Rat eradication - World's biggest
Rats and other invasive rodents have been exterminated successfully from some 300 islands worldwide, but the South Georgia project will be by far the biggest and most ambitious. The operation will involve two helicopters dropping poison bait over all ice-free land on the 170km-long island. It is vital that every rat is exterminated as they breed so fast that if just one pair survive, they can theoretically create a population of some 16,000 in just 1 year.

To support the Habitat Restoration project click here.