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Rodent eradication

Rats and the extinction of native species

The presence of exotic rodents on islands is one of the greatest causes of species extinction in the world. Rats have already been implicated in the extinction of five endemic bird species, at least 13 species of endemic invertebrates, and two plant species on Lord Howe Island.

Rodents are also a recognised threat to at least 13 other bird species, two reptile species, 51 plant species, 12 vegetation communities, and seven species of threatened invertebrates on the island. Seven of these species are listed as "Critically Endangered" under NSW and Commonwealth legislation.

Rodent eradication project

After more than 15 years of detailed research and planning, the final stage of the Lord Howe Island Rodent Eradication Project (REP) was implemented between May and November 2019.

The Lord Howe Island Rodent Eradication Program (LHI REP) aimed to eradicate introduced rodents: the Ship Rat (Rattus rattus) and the House Mouse (Mus musculus) from Lord Howe Island (LHI) and its associated islands and rocky islets (excluding Balls Pyramid), hereafter referred to as the Lord Howe Island Group (LHIG).

The eradication of rodents also presented an opportunity to simultaneously eradicate the introduced Masked Owl.

Implementation of the eradication plan

The one-off eradication plan involved the distribution of a cereal-based bait pellet (Pestoff 20R) containing 0.02g/kg (20 parts per million) of the toxin Brodifacoum across the LHIG (excluding Balls Pyramid). Methods of distribution included dispersal from helicopters using an under-slung bait spreader bucket in the uninhabited parts of the island (most of the LHIG) and a combination of hand broadcasting and the placement of bait stations in the settlement area. In dwellings (e.g. in ceiling spaces or floor spaces) bait trays and bait stations were used. Bait stations were also used inside paddocks for any remaining livestock (e.g. the remaining dairy herd, cattle and horses).

Given the size and rugged terrain of the LHIG, the exclusive use of bait stations was not deemed feasible for the eradication project.

Funding for the project

The REP has received significant funding ($10.6M). $9.5M was received in 2012 for planning and implementation from the Federal Government’s former Caring for our Country Program (now National Landcare program) $4,500,000 and the NSW Environmental Trust $4,542,442. An additional $1.1M was received from the Federal government through North Coast Local Land Services in 2019 to implement the baiting component in Winter 2019.

Visit the project website