The Island’s biosecurity program was upgraded in parallel with the REP. It has been reviewed following the detection of rats in 2021 and the Checkpoint program.
Our permanent rodent detection and incursion response system focuses on targeted monitoring of high-risk reinvasion points.
There are 83 rodent monitoring devices that are checked weekly at high-risk reinvasion points like the wharf and airport, including chew cards, wax tags, tracking tunnels and kill traps.
Our broader rodent detection network also includes devices in grids across the Island which are checked monthly. On top of 263 chew cards, wax tags, and tracking tunnels, the network also includes 162 cameras.
Lord Howe’s ongoing rodent detection network is formed by the following detection devices:
Tracking tunnels
Rodents are known for entering tunnels. Tracking tunnels use lures to provide an added attractant. The tunnels are designed to reduce non-target interference, such as by a currawong, rail or woodhen.
A plain card inside the plastic or wooden tunnel contains an ink source so that any animal that walks through it will leave footprints on the card. As a commonly used animal detection device around the world, the tunnels are highly effective at recording rodent footprints with minimum confusion with other species tracks.
To familiarise the rodents and avoid neophobia, the tunnels are put in place (without tracking cards) 6+ weeks prior to planned activation periods.
Bait stations
A network of bait stations have been placed around the settlement as part of the eradication.
The most likely rodent activity that will be recorded in the bait stations will be bait being eaten, shown through tooth marks.
Trail cameras
Trail/remote cameras are widely used to detect various species of wildlife around the world. Limited numbers have been set up around the Island.
When combined with lure, they have been very effective in confirming the presence of rodents with minimum doubt as to species identity. The cameras are particularly helpful when the presence of a rodent is suspected in an area and is used in conjunction with other methods.
Chew blocks and cards
Chew blocks/wax tags are peanut butter flavoured wax blocks with a smooth surface. When an animal bites into one, it leaves incisor tooth marks which can usually be identified to the species based on size.
Chew cards are pieces of corflute cardboard with peanut butter pressed into the holes.
Chew blocks and tags proved very useful for locating rodents during the REP, however issues with non-target interference need to be considered around the site.
Traps
Mice snap traps and DOC150 rat traps are deployed as an additional detection and kill method when active signs or suspected rodent sightings arise.
Traps kill the rodent and provide a body which can be examined for species, age, sex and breeding status.
Traps are set under covers to reduce the risk of non-target kills. The plywood covers have exclusion bars over the main entry to prevent access by birds and other non-target species. Permanent biosecurity dogs and handlers based on the Island routinely screen all incoming cargo and luggage.
Pre-border inspections of passengers, luggage and freight take place before each flight at the Eastern Air hangar and are re-inspected once on the Island.
Freight at the Birdon wharf in Port Macquarie is inspected for each voyage of the Island Trader both on mainland Australia and again on arrival on the Island.
Rodent detection dogs
Teams of specialist rodent detector dogs and handlers are the front-line defence of biosecurity on the Island.
Using scent, dogs can produce a definitive outcome as to a rodent’s location and/or presence. They can effectively detect rodents at low populations.
If the dogs indicate the current or recent presence of any rodents, other detection devices are deployed as part of a rapid response plan to confirm, locate and kill the individual(s).
Island-wide detection dog searches occur regularly as part of ongoing rodent monitoring.
Rodent detection dogs also sporadically undertake targeted searches of high-risk and random areas.