Lord Howe Island Rodent Eradication Project

Ship rats (Rattus rattus) reached Lord Howe Island, a UNESCO World Heritage-listed island 600 km off the New South Wales coast, after the 1918 wreck of the SS Makambo. Over the following century the rats drove several endemic species to extinction or near-extinction and suppressed populations of the flightless, ground-nesting Lord Howe Woodhen and multiple seabird colonies.

After more than 15 years of research, community consultation and trial baiting, the Lord Howe Island Board carried out an AUD 15.5 million eradication operation between May and December 2019 - the largest rodent eradication ever attempted on a permanently inhabited island. Aerial baiting by helicopter covered roughly 1,200 ha of forested terrain, while hand-broadcast and bait-station distribution covered the approximately 300 ha settlement area where around 350 residents live. The operation was funded by the NSW Environment Trust (AUD 4.54 million), the Australian Government and the Lord Howe Island Board.

A rat and a pregnant female rat were detected in April 2021, prompting an intensive rapid-response recapture effort that delayed final confirmation of success. Comprehensive island-wide monitoring surveys completed in 2023 confirmed no remaining rodents. Independent post-project monitoring recorded the Lord Howe Woodhen population rising from fewer than 500 birds before 2019 to more than 2,000 by 2024, and Black-winged Petrel breeding success increasing from as low as 2.5% to 67% within a year of baiting; a peer-reviewed cost-benefit study published via ScienceDirect separately documented the programme's economic case.

The 2021 rat detection is an honest reminder of the operational risk inherent in inhabited-island eradications: a single surviving breeding pair came close to requiring a second full baiting campaign, underscoring why intensive post-baiting biosecurity and monitoring for at least two years is treated as integral to the method, not optional follow-up.

Read the full analysis: https://www.lhib.nsw.gov.au/environment/rodent-eradication-project

Read the full analysis: https://www.lhib.nsw.gov.au/environment/rodent-eradication-project