About the Eradication

Key Messages

The primary goal of this project is to remove the impact of rodents on both the human population and the flora and fauna of LHI, to both improve the environment for the human residents and visitors and to provide a secure environment for populations of threatened and indigenous plants and animals currently present. Secondary goals are to remove the impact of Masked Owls on the fauna of the island and to establish a sustainable and robust biosecurity system to prevent the establishment of invasive flora and fauna including but not limited to rodents. Strengthened biosecurity measures for the Island will protect and enhance Lord Howe Islands World Heritage status and continue to increase tourism interest for this unique pest free environment. 

Need for the Project

Since the arrival of rats on LHI in 1918, residents and the Board have endeavoured to control their numbers by shooting, ratting with dogs, introducing owls and, most recently, baiting with anticoagulant poisons.

Rats are voracious predators of invertebrates. The loss of invertebrates is particularly significant because invertebrates play an important role in maintaining natural ecological functions on LHI, for example, nutrient cycling, pollination, pest control and decomposition. Two endemic land snails – Epiglypta howinsulae and a sub-species of Placostylus bivaricosus and 11 beetles are believed to have become extinct due to rodent predation. These beetles, that were present on LHI prior to the introduction of rats, have not been recorded since. This is despite significant effort including a systematic invertebrate survey by the Australian Museum between 2002 and 2004. They are also responsible for the local extirpation of the endangered LHI Phasmid Dryococelus australis, now found only on Balls Pyramid, and Wood-feeding Cockroach Panesthia lata on offshore islands including the Admiralty Group.

Rats are believed to have caused the extinction of the bridal flower (Solanum bauerianum) and native cucumber (Sicyos australis) from LHI. Rat predation on seeds and seedlings also severely reduces or stops recruitment of the little mountain palm (Lepidorrhachis mooreana) and big mountain palm (Hedyscepe canterburyana). It is thought that seed and seedling predation by rats is hindering the regeneration of the palm stand on Little Slope and rodent eradication is considered critical for the long term conservation of both little and big mountain palms on Lord Howe Island.

Rats and mice consume the seeds of many other plant species including: blue plum (Chionanthus quadristamineus), green plum (Atractocarpus stipularis), pandanus (Pandanus forsteri) and tamana (Elaeodendron curtipendulum). Rats damage the vegetative parts of a number of plant species, including all four species of palms on the island. Rats damage the bark on the trunk and limbs of a number of tree species, including Sally wood (Lagunaria patersonia), tamana and island apple (Dysoxylum pachyphyllum). In severe cases this can result in the death of the tree. Other indirect effects that rats have on vegetation include the reduction of habitat of some invertebrates and the removal of some food resources that would otherwise be used by birds.

Eradication vs. Control

This project is about the eradication of rats and mice from Lord Howe Island. Eradication is different to control even though they sometimes use the same tools. Control seems simple and we have been doing it on the Island for nearly 100 years but it is actually the more difficult and costly of the two strategic options.

Control means:

  • Managing the populations to a level where they are still there but their harm is not a significant problem. The key to this is being able to sustain the control effort because if you stop control the rodents breed back, so this is a never-ending job.
  • Because it is never-ending, the costs mount up over time – both money to do the work and environmental effects of the tools being used.
  • Because of the cost, control is often limited in the size of area able to be covered sustainably. Limited area equals limited benefits. The current control program on LHI protects 10% of the island.
  • Because it is ongoing, control is effectively a selective breeding program where those individuals who survive the control methods being used are able to breed and pass on their genes. So we end up in an “arms race” inventing new tools or methods to control rodents which are no longer vulnerable to our old methods.
  • From an animal welfare perspective, because it is never-ending, more rodents are killed over time than a one-off eradication project.


  • Means getting every single individual all in one operation and making sure rodents are not able to return to the Island.
  • To ensure we get every last one, the design must be thorough. Every step is motivated by the need to minimise the risk of leaving individuals behind – this is the cheapest and most environmentally friendly way to approach eradication because it avoids having to repeat effort in the future.
  • Making sure they can’t get back means putting systems in place to check and stop rodents leaving the mainland, searching for any that may have got through and responding rapidly to any indication of invaders. These systems have the added advantage of stopping other undesirable pests as well for little extra cost.

Techniques for eradicating rodents from islands the size of Lord Howe Island have been successfully used for over 20 years, with a recent example being Macquarie Island (12,800 Hectares) in the Southern Pacific Ocean successfully eradicating all rodents and rabbits in 2014. Although it is expected that some non target species impacts will occur during an eradication program, these species are expected to recover quickly to pre project levels very quickly after the baiting program.  Consequently, a continuing an ongoing program of control can never deliver the same level of biodiversity benefits as eradication.

Current and Future Impacts of Rodents

Rats and mice are currently having a significant impact on the World Heritage, community and economic values of Lord Howe Island. They prey on and compete with a variety of threatened animals and plants, and impact community amenity though hygiene issues and spoiling of food stuffs. Eradication (rather than ongoing control) will provide the following benefits:

  • Increased productivity for the Kentia Palm industry
  • Elimination of possible health issues and amenity impacts to tourism operations (e.g. baiting in lodges and other accommodation).
  • Significant biodiversity improvement including threatened species recovery and reintroduction (e.g. LHI phasmid). 
  • Removal of ongoing poison in the environment and associated control costs. The Lord Howe Island rodent control program (excluding residents’ own poison usage) has used more than 130 tonnes of poison over the last 30 years costing over $2 million dollars. 
  • An end to rodenticide resistance on Lord Howe. Mice have become resistant to warfarin due to over exposure in previous control programs and recent testing has shown an increase in resistance to brodifacoum in the settlement area where residents use Talon (brodifacoum based) to control rodent numbers.
  • Long term positive impacts for tourism through protection and enhancement of World Heritage values and improved visitor experience. For example, on Ulva Island in New Zealand, an eradication of rodents was undertaken in 1996. The success of the eradication, and subsequent reintroduction of species lost from the island as a consequence of rat predation, has resulted in the island becoming a premier tourist location. Tourist numbers increased from around 10,000 to 30,000 per year in the decade after rat eradication. This boost in tourism resulting from ecosystem recovery sustains 17 new businesses.

Project Description

If the program proceeds, LHI will be the largest, permanently populated island on which the eradication of exotic rodents has been attempted to date. The evidence shows that the best long-term solution is to eradicate both rats and mice from the LHI Group in a single eradication operation. However, given the island’s permanent human population, its highly developed tourism industry and its endemic and threatened species, considerable planning is currently being undertaken to ensure all environmental and human health issues are thoroughly examined during the Planning and Approval stage.

Many methods of eradication have been carefully investigated in order to identify the one most suited to the LHI Group, including a number of different toxins and different means of delivering them, as well as undeveloped and unproven viral methods.

Based on data from over 300 successful eradication programmes on islands around the world, the proven and most effective method will be to distribute poison baits by three main methods, aerial, hand broadcasting and bait stations. The bait, Pestoff 20R®, contains brodifacoum and trials have shown it is highly palatable to both ship rats and house mice. It is proposed to deliver the bait via the three delivery options to all rodents on the island as quickly as possible to avoid gaps in the bait coverage over the landscape. No aerial application will be undertaken over the settlement areas, where there are houses and where people live.

The project has been proposed to be undertaken in the winter of 2017 to 2018 providing all approvals have been obtained from the relevant authorities.

Concerns about the method of delivery, interaction with soil and water, impact on the marine environment, impact on non-target species and efficacy will be addressed during the current assessment process. The Board has engaged with the NSW Chief Scientist and Engineer regarding a detailed human health risk assessment.

Project Stages

Project Timelines

The overall Project timeline is shown below. We are currently in Phase 2.





















Project Progress

Following the majority vote by the community on the eradication option in May 2015 and the Board’s decision to proceed, we have moved into Phase 2 of the project: the Planning and Approvals Phase. In this phase we are:

  • Continuing community engagement through discussion of individual Property Management Plans and addressing community concerns  
  • All the required regulatory approvals and permits applications including information required to support these applications has been completed and submitted to the responsible authorities during 2016 and early 2017. It is expected that all key regulatory decisions and all approvals will be received before the Boards decision in September 2017.  

Continuing to plan for implementation of the eradication subject to receiving all approvals and the Funding Bodies and Board’s Final Go / No Go decision

Phase 2

The Approvals Process

There are numerous State and Federal government regulatory approvals and permits required before the eradication can commence.  Individual regulatory agencies will comprehensively assess the proposed project risks, potential impacts and proposed mitigation along with available evidence, relevant to their jurisdiction and make independent decisions on whether or not to approve the applications. Many of the approvals and permits have statutory public comment periods. The agencies may also set conditions to be adhered to as part of any approvals granted.  If all approvals are not received, the eradication program will not proceed.

To view the recently submitted application click the following links:

Australian Pesticide and Veterinary Medicines Authority (APVMA) Application PDF 3.8 MB 

APVMA Supporting Documents PDF 8.6 MB

The full referral under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and supporting documents can be found below

EPBC Householder PDF 125 KB

EPBC Referral PDF 1.9 MB

EPBC Attachment 1 - Maps PDF 1.1 MB

EPBC Attachment 2 - Captive Management PDF 2 MB

EPBC Attachment 3 - Masked Owl PDF 2.6 MB

EPBC Attachment 4 - Community PDF 2.5 MB

EPBC Attachment 5 - PMST PDF 303 KB

EPBC Attachment 6 - LHI Trials PDF 1.8 MB

EPBC Attachment 7 - Marine PDF 322 KB

If all approvals are not received, the eradication program will not proceed.

Go / No Go Decision

The final decision on whether or not to proceed with the eradication will be made by the project’s funding bodies and the Board based on:

  • Status of approvals
  • Additional advice from the NSW Chief Scientist and Engineer
  • Ongoing community consultation
  • Technical, social and financial advice

It is expected that this decision will occur September 2017.

Property Management Plans

The Property Management Plans (PMPs) include the agreed baiting methods for each lease on the Island, including the settlement area. They are discussed and negotiated with the leaseholders / residents individually and consider mitigation of specific risks and areas of concern on individual properties. The PMPs will only need to be finalised once all government approvals have been received and the final decision to proceed with the eradication project has been made by the Board.  The PMPs will not impact on the tenure of the leases. As discussed during the Property Management Planning process, livestock owners will only begin reducing their cattle numbers in preparation for the operational phase if it proceeds.

Will the project progress if not everyone agrees

The Board will to act keep the Island’s people safe and to protect the Island’s environment, World Heritage status and unique tourism assets. With that principle in mind the Board will make a final technical, social and financial decision on whether to proceed with the eradication or not at the end of the Planning and Approvals Phase. Not everyone may agree with the final decision.

Has the baiting approach been decided?

The overall baiting approach has been decided and will be put forward in the approvals and permit applications for the various regulators to approve. This includes aerial broadcasting over uninhabited parts of the island and a combination of hand broadcasting and bait stations in the settlement area.  Alternate methods will continue to be assessed for feasibility leading up to and during the approvals process.  Conditions of approvals, when received from the various government agencies, may also influence the final baiting approach.  The actual treatment methodology over individual properties will be discussed and negotiated with individual leaseholders and residents through Property Management Plans but will be in accordance with any regulatory approvals or conditions received.

Phase 3

The Implementation Phase

This phase will only happen if the decision is made to proceed with the eradication. This phase of the proposed eradication program involves the actual distribution of bait and the monitoring of its impact. It will last as long as the aerially and hand-broadcast baits persist in the environment as determined by field monitoring. However, this period is weather-dependent and the actual period of risk will be determined by the measured rate of bait disintegration. Bait stations will be placed in and under buildings and other agreed locations in consultation with island residents. 

Prior to the commencement of any baiting activities, capture of woodhens, currawongs and other species requiring captive management during the operational phase will be undertaken. Other activities will include:

  • purchasing bait and materials
  • contracting appropriate helicopter, aviculturist and veterinarian support
  • constructing aviaries and on-island captive management facilities
  • mapping of flight lines
  • improving quarantine procedures to ensure the chance of reinfestation are eliminated
  • establishing all monitoring programs.

All procurement procedures will follow relevant NSW Government guidelines and policies.

How will the baiting be undertaken and over what time period?

Baiting will be undertaken using a combination of aerial, hand broadcasting and bait stations. No aerial baiting will be undertaken over the settlement area. The aerial and hand broadcasting will be undertaken twice over a 21 day period to minimise any gaps in the bait broadcast and expose any surviving young that have recently emerged from the nest after the first baiting. Bait stations around the settlement area will be monitored by work crews and loaded with bait as required.

After a non-toxic baiting trial on Lord Howe Island in 2007, results showed that both 5.5 mm and 10mm baits in all three habitats were in advanced stages of decomposition after 55 days and 164.2 mm of rainfall.  Further monitoring showed that all baits had completely disappeared by 100 days.

Bait stations will be physically removed from properties after intensive monitoring has found no sign of rodent activity and Project Managers are confident that all rodents have been eradicated. 

What will happen to all the dead rodents after the baiting has occurred?

It is estimated that 50-70 employees, many from the island community, will be required for the eradication operational phase to assist with its implementation. With the bait station monitoring continuing throughout the settlement area, crews will also be engaged in collecting as many dead rodents as possible and disposing of them appropriately to minimise the impacts to residents and the environment.      

Phase 4

How do we keep rodents off the island after the eradication?

The LHI Biosecurity Strategy has recently been revised to significantly increase the level of protection from introduction (or reintroduction) of invasive species. It is important to note that biosecurity on the island will be improved regardless of whether or not the rodent eradication proceeds, in order to keep a wide range of invasive plants and animals off the island.  If the eradication does proceed, special consideration will be given to keeping rodents off the island. The Biosecurity Strategy will continue to be revised and updated during and after the REP process.