Action: Control predators not on islands for rails
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A single study from the USA found more California clapper rails Rallus longirostris obsoletus on sites with higher numbers of foxes removed.
Supporting evidence from individual studies
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.