Island seabird population surges after successful rat eradication drive

D'Arros Island's Wedge-tailed Shearwater colony has experienced a remarkable resurgence following the eradication of rats from the island two decades ago. Successive surveys have documented the scale of this recovery, with researchers recording 2,768 breeding pairs in 2016, followed by 2,406 pairs in 2021, representing a dramatic increase from pre-eradication levels.

The expanding population has not only grown in numbers but also spread across a larger geographic area of the island. Researchers noted significantly higher breeding burrow density during later surveys, indicating that the shearwaters have successfully recolonized previously uninhabitable portions of D'Arros Island following the removal of the invasive rat population that had previously decimated their breeding grounds.

Scientific monitoring employed direct counts and area-based estimation techniques to accurately track breeding pair numbers across successive survey periods. This methodological consistency has enabled researchers to establish reliable population trend data and benchmark the recovery trajectory of the colony.

Identifying the peak incubation period occurring in November proved critical for establishing a standardized monitoring framework. This timing benchmark will enable future surveys to be conducted during optimal conditions for accurate breeding population assessments, ensuring continued tracking of the shearwater colony's long-term health and stability.