A major conservation win: invasive black rats eradicated from North West Island

Issued

27 April 2026

Region

Gladstone

North West Island in the Great Barrier Reef World Heritage Area has been declared rat-free, a significant win for the conservation of threatened turtles and seabirds.

The declaration follows an intensive 18-month eradication program led by the Queensland Parks and Wildlife Service (QPWS) and Gidarjil Land and Sea Rangers, followed by 12 months of monitoring that found no evidence of rats remaining on the island.

For an island that supports important populations of nesting seabirds and marine turtles, the outcome is a major achievement toward protecting these species and restoring the health of the island’s precious and biologically diverse ecosystem.

Image 1 (left): Aerial view of a small, forested tropical island surrounded by turquoise water and white sandy beaches. Image 2 (right): A Ranger stands in coastal woodland holding a metal cage trap with a black rat inside.

Why are black rats such a problem?

A single breeding pair can multiply quickly, capable of creating a population in the thousands within a year. On isolated islands, where many native species evolved without mammal predators, the introduction of rats can be especially destructive.

They are omnivorous, meaning they will eat almost anything. On North West Island, that includes:

seabirds, their eggs and chicks

turtle eggs and hatchlings

native vegetation

Due to North West Island’s exceptional environmental values, the rat eradication project became a key priority for QPWS and the Gidarjil Land and Sea Rangers.

Image 1 (top left): A hatchling sea turtle crawls across wet sand toward the ocean at sunrise, with gentle waves and a clear sky. Image 2 (top right): Black seabirds perch on leafy branches around a nest in a coastal tree canopy. Image 3 (bottom right): A small animal rests inside a shallow burrow beneath exposed tree roots in sandy soil.

Black rats can have devastating impacts on turtle hatchlings and seabirds.

Photo credit: Turtle: © Jon Mills

How were the rats discovered?

The infestation was first reported to QPWS in November 2022 by diligent campground hosts on the island.

Following the reports, Rangers deployed remote cameras and Black Trakka ink monitoring stations which confirmed that black rats had spread throughout the island.

This was especially disappointing because mice had been declared eradicated from the island just three months earlier, highlighting how quickly pests can be reintroduced and how important strong biosecurity measures are for island conservation.

Black-and-white camera trap image showing a small a black rat a rectangular ink monitoring station at the base of a tree.

How were the rats eradicated?

Eradicating invasive species from an island is a complex task that requires careful planning, persistence and flexibility.

Because of the size of North West Island, aerial baiting by helicopter was identified as the most effective form of treatment to maximise the chances of success. However, bait stations and trapping were also used to help reduce the impacts on seabirds and turtles.

According to Senior Ranger Damon Shearer, the eradication team frequently altered their tactics to adapt to the rats’ changing behaviour over time.

Monitoring after treatment

Declaring an island pest-free is not something that happens immediately after baiting or trapping ends. Once the eradication program was complete, Rangers used remote cameras and Black Trakka traps to monitor for rats.

Only after a full year of intensive monitoring with no signs of black rats was North West Island officially declared rat-free.

Image 1 (left): A Ranger crouches at night in coastal scrub, checking a small ink monitoring station on the ground using a headlamp. Image 2 (right): A Ranger kneels on the forest floor checking an ink monitoring station.

Rangers are urging the public to thoroughly check gear and boats before coming to the island.

Working together for conservation

The project was delivered by the Great Barrier Reef Marine Park Authority and QPWS through the Reef Joint Field Management Program, with funding through the Australian Government’s Reef Trust by Australia Pacific LNG, QGC and Santos GLNG.

It also reflects the value of collaboration on the ground, with QPWS Rangers and Gidarjil Land and Sea Rangers proud of the hard work they put in together to protect one of the Great Barrier Reef’s important island habitats.

Be pest-free when visiting the Great Barrier Reef islands

The isolation of many islands make them particularly vulnerable to pest impacts and this biosecurity risk threatens their World Heritage values. Overall, the best way for a pest to get to an island is to travel with visitors who unknowingly carry them over and leave them there.

A pest hiding in your gear or boat might seem harmless, but even small pests pose a big threat to our world heritage-listed islands.

Currently the precious Great Barrier Reef World Heritage islands are the most pest-free islands in the world. If you’re visiting an island you can help to keep it that way.

Read the Be pest-free! web page or watch Protecting the Great Barrier Reef: Biosecurity tips for more information.