Ship rat Rattus rattus eradication on Pein Mal Island, Federated States of Micronesia, Pacific Ocean

  • Published source details Wegmann A., Braun J. & Neugarten R. (2008) Ship rat Rattus rattus eradication on Pein Mal Island, Federated States of Micronesia, Pacific Ocean. Conservation Evidence, 5, 28-32.


As part of a larger project attempting to reduce predation pressure from introduced rats Rattus spp. on native fauna and flora on several islands off Pohnpei main island (Pacific Ocean), a rat eradication program was undertaken on the small island of Pein Mal (2.17 ha) where ship rats R.rattus were present. The island was systematically hand-broadcast with rodenticide bait at a pre-determined application rate of 50 kg/ha over one day. Radio-tracking revealed that rats spent a significant amount of time in the forest canopy. Therefore, to ensure that rats living in the canopy had a good chance of encountering bait, bait clusters (bolo baits) were made and catapulted into one third of the palm trees on the island. Mangrove forest surrounds the shore of Pein Mal where rats were also present. Throughout this habitat to ensure rat access to the rodenticide, a bait station grid was established with bait stations nailed to tree trunks approximately 2 m above the high water mark. Pre-bait application trap success (rat captures/trap nights) was 39%. Post-bait application trap success (as recorded 10-14 days after bait application) was 0%. Pre-bait application wax indicator success was 53%. Post-bait application wax indicator success was 0%; subsequent monitoring 6-months later detected no rats. No non-target species appeared adversely effected by the bait.


Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust