Invasive species and conservation: Papers

The eradication of feral cats from Ascension Island and its subsequent recolonization by seabirds

Norman Ratcliffea1 p1 c1, Mike Bella2, Tara Pelembea3, Dave Boylea2, Raymond Benjamina3, Richard Whitea1, Brendan Godleya4, Jim Stevensona1 and Sarah Sandersa1

a1 RSPB, The Lodge, Sandy, Bedfordshire, UK.

a2 Wildlife Management International Ltd, Blenheim, New Zealand.

a3 Ascension Island Government Conservation Department, Georgetown, Ascension Island, South Atlantic.

a4 Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK.


The introduction of mammal predators to islands often results in rapid declines in the number and range of seabirds. On Ascension Island the introduction of cats in 1815 resulted in extirpation of large seabird colonies from the main island, with relict populations of most species persisting only in cat-inaccessible locations. We describe the eradication of feral cats from this large and populated island. The campaign had to minimize risk to humans and maintain domestic animals in a state that prevented them re-establishing a feral population. Feral cat numbers declined rapidly in response to the strategic deployment of poisoning and live trapping, and cats were eradicated from the island within 2 years. During the project 38% of domestic cats were killed accidentally, which caused public consternation; we make recommendations for reducing such problems in future eradications. Since the completion of the eradication campaign cat predation of adult seabirds has ceased and five seabird species have recolonized the mainland in small but increasing numbers. Breeding success of seabirds at Ascension was low compared to that of conspecifics elsewhere, and the roles of food availability, inexperience of parent birds and black rat predation in causing this warrant further investigation. It is likely that the low breeding success will result in the rate of increase in seabird populations being slow.

(Received May 08 2009)

(Reviewed July 23 2009)

(Accepted August 26 2009)


c1 RSPB, The Lodge, Sandy, Bedfordshire, UK. E-mail notc@bas.ac.uk

p1 Current address: British Antarctic Survey, Natural Environmental Research Council, High Cross, Madingley Road, Cambridge, CB4 0ET, UK.


This paper contains supplementary material that can be found online at http://journals.cambridge.org