Mice as sole introduced mammalian pest species.

Written by Chrissy Wickes

Mice on Antipodes. Photo by J.Russell

Mice on Antipodes. Photo by J.Russell

What happens when mice are the only introduced mammalian pest on a seabird island?

Rats will predate and dominate mice when they co-habitat an island, occupying the best habitat and out competing them for the best food. When mice are the sole mammalian pest species they can impart insidious and compounding effects and cause significant damage.

Interesting research from Gough Island, another Southern Ocean island, has revealed mice develop unusual behaviour when they are the sole introduced mammalian pest species.

“Where mice are the only introduced mammal, a greater range of native biota is impacted and the impacts are most severe and include the only examples of predation on seabird eggs and chicks” (Angel et al., 2009).

Like the Antipodes Islands, Gough Island now has only one introduced mammalian pest species, the house mouse (Mus musculus). Studies on Gough Island show that mice were responsible for 57% of Tristan albatross (Diomedea exulans sensu lato) chick failures in 2001 and 2004. Also on Gough Island mice have been responsible for the predation of chicks and or eggs of Atlantic Yellow-nosed albatross, Sooty albatross, Atlantic petrels and Gough bunting.

Tristan Albatross chick being eaten by mice. Photo by Ross Wanless and A. Angel

Tristan Albatross chick being eaten by mice. Photo by Ross Wanless and A. Angel

Tristan Albatross severely wounded by alien mice on Gough Island in 2012. Photo by Sylvain Dromzée.

Tristan Albatross severely wounded by alien mice on Gough Island in 2012. Photo by Sylvain Dromzée.

Mice on Gough Island were confirmed attacking and killing chicks 300 times their own weight (Wanless et al., 2007).

Further evidence of possible mice predation on chicks has been observed on Marion Island where severe wounds were found on albatross chicks (Angel & Cooper 2006). This again is an island where mice are the sole mammalian pest species.

Very little research has been done on the impacts of mice on seabirds on Antipodes because of its remoteness and the associated expenses. Therefore there is currently no evidence that the mice on Antipodes are predating on sea or land bird species, but evidence from Gough Island strongly suggests there is potential for this to happen on the Antipodes. “We argue that similar mouse predation may have been overlooked elsewhere, and may be most likely where mice are the sole alien mammal.” (Wanless et al 2001).

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Resources:

Angel A. & Cooper J. 2006. A Review of the Impacts of Introduced Rodents on the Islands of Tristan Da Cunha and Gough.RSPB Research Report No.17.Royal Society for the Protection of Birds, Sandy, United Kingdom.

Angel A., Wanless R.M.,Cooper J. 2009. Review of impacts of the introduced house mouse on islands in the Southern Ocean: are mice equivalent to rats? Biol Invasions, 2009, 11:1743–1754.

Wanless R. M., Angel A., Cuthbert R. J., Hilton G. M., and Ryan P. G. 2007. Can predation by invasive mice drive seabird extinctions? Biol. Lett. (2007) 3, 241–244.