CATS ON THE PELLEW ISLANDS
The drastic declines in mammal populations across northern Australia during the past two decades have been reflected on the Pellew Islands, situated in the south-west of the Gulf of Carpentaria. Cats were introduced to several of the islands in the 1990s, and since then researchers have watched small mammal populations plummet. A collaborative project to eradicate cats from West Island was initiated between li-Anthawirriyarra Sea Rangers, the Parks and Wildlife division of the NT Government and Rachel Paltridge from Desert Wildlife Services. West Island had seen the disappearance of nearly all its small mammals with five consecutive fauna surveys from 2003-2011 failing to capture a single mammal. At this point it was feared that all native mammals had been extinguished from the island since the cats had bred up and taken over.
Since 2010, this project has primarily been funded by TNRM. Results from a pilot study on the island in July 2010 indicated cat sausage baits could be a successful method of controlling this destructive predator. After an integrated cat control program of trapping, tracking, spotlighting and baiting the team has seen a significant reduction in cat numbers. Cat control has mainly been achieved through poison baiting but the Sea Rangers are now also proficient at using leghold traps.
In contrast to the ongoing decline of small mammals across the Top End over the last decade, West Island is bucking the trend and showing a spectacular recovery of native mammals. Now Grassland Melomys can be found in every creek and the beachfront dunes are teeming with Delicate Mice. Water Rats are also regularly detected. Concurrent monitoring on a neighbouring island where no predator manipulation has occurred has shown no increase in native mammal populations during the study period.
Wildlife Ecologist Dr Rachel Paltridge who assists the the li-Anthawirriyarra Sea Rangers Sea Rangers with the project is thrilled with the results.
“Although there are many examples of Natural Resource Management being attempted across the NT, it is a rare achievement to be able to measure significant outcomes in both the reduction of the threatening process and an improvement in the asset being protected” Dr Paltridge said.
“This is a good news story that demonstrates the benefits of having highly skilled Indigenous Rangers working in collaboration with scientists to restore land and sea country. The Sea Rangers have persisted with this project for five years now, and have become experts in cat control.”
Although the West Island cat population appeared to show some sign of recovery over the 2014/15 wet season, aerial and ground baiting conducted throughout the island in June 2015 has again reduced the cat population to the point where sign of only a single cat was found during the August survey. West Island is the first site in the NT licensed to use the Eradicat bait, which is a bait specifically designed for feral cats that has achieved good conservation outcomes in Western Australia. The West Island cat control project has been conducted by the li-Anthawirriyarra Sea Rangers based in Borroloola, in collaboration with Dr Rachel Paltridge from Desert Wildlife Services, with assistance from Traditional Owners of West Island and NT Parks and Wildlife Rangers based in Borroloola.
The project is supported by Territory Natural Resource Management through funding from the Australian Government’s National Landcare Programme.