Modify traps used in the control/eradication of non-native species to avoid injury of non-target mammal
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
A range of live-trapping techniques is used in control activities aimed at non-native species. As traps may capture species additional to the targeted non-native species, using live traps enables release of those non-target captures. However, restrained mammals are at risk of suffering injuries prior to being released. This intervention considers cases where modifications might be made to live traps with the intention of reducing such incidental injuries.
Supporting evidence from individual studies
A before-and-after study in 2006–2010 on an offshore island in California, USA (Jolley et al. 2012) found that modifying traps used to control non-native cats Felis catus reduced moderate but not severe injuries among San Nicolas Island foxes Urocyon littoralis dickeyi. These results were not tested for statistical significance. A lower proportion of San Nicolas Island foxes that were caught in modified traps (4%) suffered moderate injuries than when unmodified traps were used (25%). However, the rates of severe and very severe injuries in San Nicolas Island foxes were similar (around 5%) between the periods when modified and unmodified traps were used. The study was conducted on a 5,896-ha island. During 20 days in 2006, sixty-four San Nicolas Island foxes were caught with leg-hold traps deployed to catch non-native cats. Between June 2009 and January 2010, using modified leg-hold traps, 1,011 Nicolas Island foxes were caught. Trap modifications included a shorter anchor cable and chain, lighter spring, and additional swivels to allow unrestricted rotation of the trapped animal. Traps were checked remotely 24 hours a day to reduce the time foxes spent in the traps.Study and other actions tested
Referenced paperJolley W.J., Campbell K.J., Holmes N.D., Garcelon D.K., Hanson C.C., Will D., Keitt B.S., Smith G. & Little A.E. (2012) Reducing the impacts of leg hold trapping on critically endangered foxes by modified traps and conditioned trap aversion on San Nicolas Island, California, USA. Conservation Evidence, 9, 43-49