Impact of Feral Cats on the Tiwi Islands

Australia has the highest rate of mammal extinction on Earth, primarily due to predation by feral cats and foxes. These extinctions have occurred mostly in southern and arid parts of Australia but over the last 30 years many mammal species have disappeared from across the north, including possums, bandicoots and quolls. The reasons why these species are disappearing are complex, but are thought to be related to frequent, hot fires making it easier for predators such as feral cats to hunt.

The Tiwi Islands are special because they are one of the last refuges for small mammals that are regionally extinct in many parts of mainland Australia, but research has shown that some of these mammals may be in decline. Traditional food sources are still an important part of the Tiwi diet and play a critical role in providing healthy food options. Hunting activities reinforce traditional authority structures, are an important way of passing on traditional knowledge, and form the basis for cultural land management. If small mammal populations decline, it is likely there will be significant impacts on the expression of Tiwi culture.

Using traps and motion-triggered cameras, scientists and the Tiwi Land Rangers compared the number of small mammals recorded in 2015 on Melville Island with the number recorded in 2000. There were fewer recorded sightings of Kipopi (Northern brown bandicoot – Isoodon macrourus), Pwampungini (Black-footed tree-rat – Mesembriomys gouldii) and Rataka (Brush-tailed rabbit-rat – Conilurus penicillatus), which is one of 20 priority mammals in the Australian Government’s Threatened Species Strategy. No declines were recorded for Wuninga (Northern Brushtail possum -Trichosurus vulpecula). More work needs to be done on Bathurst and Melville islands on small mammals, feral cats, fire, and natural population fluctuations caused by rainfall, to work out the cause of these declines.

The research was a collaboration between the Tiwi Land Council, the University of Melbourne, CSIRO and Charles Darwin University, with support from the Northern Territory Government and the Threatened Species Recovery Hub of the Australian Government’s National Environmental Science Programme.

Where to from here?

The Tiwi Land Council has been proactive in working with Animal Management in Rural and Remote Indigenous Communities, the University of New England and The Ark Animal Hospital, with support from the Australian Government’s Threatened Species Commissioner, to promote a cat-free Tiwi Islands. In contrast to many other Aboriginal communities, Tiwi people generally do not keep cats as pets, and there is overwhelming community support for feral cat control.  The Tiwi Land Council is also working with scientists, with support from the Norman Wettenhall Foundation, to determine how many feral cats are on the Tiwi Islands. A better understanding of the role of frequent fire, the ecology of feral cats and other ecological processes is required to manage impacts on threatened and culturally important small mammals.  Armed with this knowledge, Tiwi leaders will be able to develop and implement effective management strategies to protect the nationally significant biodiversity and cultural values of the Tiwi Islands. 

Resources

Cats and Wildlife on the Tiwi Islands brochure

Cats and Wildlife Don't Mix poster

Nyirramangi Pijikati poster

Caring For Cats poster 

Cat Ownership and Small Mammals on the Tiwi Islands brochure