Diet patterns of island foxes on San Nicolas Island relative to feral cat removal

  • Published source details Cypher B.L., Kelly E.C., Ferrara F.J., Drost C.A., Westall T.L. & Hudgens B.R. (2017) Diet patterns of island foxes on San Nicolas Island relative to feral cat removal. Pacific Conservation Biology, 23, 180-188.


This study is summarised as evidence for the following.

Action Category

Remove/control non-native mammals

Action Link
Terrestrial Mammal Conservation
  1. Remove/control non-native mammals

    A before-and-after study in 2006–2012 of scrubland on an island in California, USA (Cyper et al. 2017) found that following removal of feral cats Felis catus, vertebrate prey increased as a proportion of the diet of island foxes Urocyon littoralis. The frequency of deer mice Peromyscus maniculatus in fox scats was higher after cat removal (40%) than before (11%). The same pattern held for birds (after: 12% of scats; before: 6% of scats). Lizard frequency in fox scats was not significantly higher after cat removal (10%) than before (5%) and there were not significant changes in frequencies of arthropods, snails or fruit. Authors indicated that increased deer mouse and bird frequency suggests that foxes and cats had been competing for prey. However, fox abundance was more linked to precipitation levels, and declined over the study period. On a 5,896-ha island, feral cats were eradicated in 2009–2010. Fox scats collected before cat removal (1,180 scats, autumn 2006–summer 2009) and after removal (508 scats, autumn 2010–summer 2012) were analysed for food remains.

    (Summarised by: Nick Littlewood)

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