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Providing evidence to improve practice

Individual study: Effects of feral cat Felis catus eradication and black rat Rattus rattus control on sooty terns Onychoprion fuscata nesting at Waterside and Mars Bay, Ascension Island

Published source details

Hughes B.J., Martin G.M. & Reynolds S.J. (2008) Cats and seabirds: effects of feral domestic cat Felis silvestris catus eradication on the population of sooty terns Onychoprion fuscata on Ascension Island, South Atlantic. Ibis, 122-131


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Control mammalian predators on islands for seabirds Bird Conservation

A before-and-after study over 17 years (1990-2007) on Ascension Island (88 km2), South Atlantic (Hughes et al. 2008), found that the sooty tern Onychoprion fuscata population increased (though not significantly) from 302,000-417,000 birds (1990 and 2001) to 420,000 (2007), following feral cat Felis catus eradication in 2002-4. The authors note that no increase would be expected until 2008 due to the breeding cycle of the terns. Predation by cats fell from 33 birds/night (early 1990s) to zero  birds/night (2003), and overall nesting success rose from 54% of 233 nests to 68% of 656 nests. Following cat eradication, there was a significant increase in the number of tern chicks being predated by rats, from zero prior to cat eradication (473 days of monitoring) to 46% of 200 chicks ringed in 2005 (40 days of monitoring). Cats were removed through poisoning (with 1080 sodium monofluoroacetate), trapping and other methods (started in 2002, completed 2004).