Norway rats (Rattus norvegicus) on Fregate Island, Seychelles:: the invasion;: subsequent eradication attempts and implications for the island's fauna

In July 1995 Fregate Island in the Seychelles was colonised by Norway rats (Rattus norvegicus). Prior to this date, Fregate was the largest rat-free island in the inner, granitic, group of the Seychelles archipelago. An eradication attempt was made in June 1996 to protect the unique fauna of the island, including the critically endangered Seychelles magpie-robin (Copsychus sechellarum). This was the first time an attempt had been made to eradicate a newly arrived and rapidly expanding rat population. The attempt was abandoned after several Seychelles magpie-robins died through secondary rodenticide poisoning. Possible biological consequences of continued rat presence on Fregate Island an discussed and recommendations made that are relevant to other invasions of islands by rats. This is the first time that a rat invasion of a biologically important conservation island has been documented in any depth. (C) 2000 Elsevier Science Ltd. All rights reserved.