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Providing evidence to improve practice

Individual study: Red fox Vulpes vulpes control achieves short-term increases in populations of the endangered California clapper rail Rallus longirostris obsoletus, in the San Francisco Bay area of California, USA

Published source details

Harding E.K., Doak D. & Albertson J.D. (2001) Evaluating the effectiveness of predator control: the non-native red fox as a case study. Conservation Biology, 15, 1114-1122


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

Control predators not on islands for rails Bird Conservation

An analysis of data from 24 sites in south San Francisco Bay, USA, between 1991 and 1996 (Harding et al. 2001) found that the number of California clapper rails Rallus longirostris obsoletus surveyed each winter was positively correlated with the capture rate of red foxes Vulpes vulpes the previous year. At one site, the rail population increased from 40 in 1989 to 104 in 1994. Over the study period, the number of foxes trapped remained relatively constant (66-94/year) despite increased trapping effort, suggesting population decline.  However, the authors suggest that fox immigration into the area meant that predator control would only be effective in the short term.