Feral Animals of Australia: Rabbits

Many of us all over the world grew up learning about rabbits from books like Peter Rabbit by Beatrix Potter and sympathised with Peter as he is chased out of the garden by Mr McGregor. But in Australia rabbits cause losses in the hundreds of millions of dollars every year. They may be cute to some, but rabbits have had an enormous impact on the native flora and fauna as well as the agricultural and livestock industries. There have been many attempts to control numbers, some of which have worked quite well. New methods are now being sought to finally rid Australia of its most detested pest.

Many species have been introduced to Australia only to become widespread pests, and none more so than the rabbit (Oryctolagus cuniculus). Rabbits are found in most areas of Australia except for the most northern parts, rainforests and high altitudes, so long as the soil is suitable. While most would associate rabbits with underground warrens, rabbits can also live above ground and seek shelter in hollow logs. Feral rabbits live up to the age of six and females can produce up to 40 offspring a year (though most will not survive to maturity). In the wild rabbits eat grass, shoots and weeds.

Feral rabbits were first brought to Australia from Great Britain with the First Fleet in 1788. The rabbit population flourished first in Tasmania, and then on the mainland. After an initial release in Victoria 1859, rabbits were either released for the purposes of hunting for sport or escaped accidentally. While the landscape changed somewhat after the introduction of rabbits, they have continued to multiply to plague proportions in many areas of the country.

Damage Caused by Rabbits :

• Prevent young native plants from growing, leading to a permanent reduction in shrubs and trees once the mature plants die off.

• Soil erosion from burrowing.

• Damage to valuable crops.

• Competing with native fauna for nutritious food.

• Dramatically reduce the amount of livestock that can be kept on rabbit-infested land by again competing for food.

Some people believe that the rabbit, although introduced, has as much right to survive in Australia as the native flora and fauna. It is true that wild rabbits are the number one source of food for many native predators. With no rabbits, raptors, feral foxes and feral cats would turn to native marsupials, lizards and birds, some of which may already be endangered. A decline in rabbit numbers, may therefore also effect those predators. However, the damage that rabbits cause to the Australian landscape is far too great to ignore.

Many methods are used to try to control the rabbit infestation. None is a miracle cure on its own but Government departments, research organisations such as the CSIRO, along with local landcare groups are working to find the most effective and inexpensive combination. Fencing in properties to exclude feral animals including foxes, cats and dingo is one example of a temporary solution which is very costly for the landowner. It does nothing about the growing numbers of animals outside, and the special type of fence needed to prevent burrowing under or crawling through is expensive. It is just not feasible for owners of large properties.

Timeline of Large-Scale Rabbit Control Methods:

1859 onwards= Shooting was the main method for killing feral rabbits. Unfortunately this was ineffective and rabbit numbers grew enormously out of control. After the spread of the rabbits throughout the mainland of Australia, some cats and foxes were released to prey on rabbits.

1950= The virus myxomatosis was officially released in Australia and did wonders to reduce rabbit numbers in certain areas, but not enough. The virus still exists today though many rabbits have developed a resistance to it.

1968= The European rabbit flea was introduced to continue to help fight rabbit numbers in the wake of myxomatosis.

1980's= Steel-jawed leg holding traps were banned in most states of Australia because they were seen as inhumane. Steel traps caught and caused pain to other innocent species but s oft (padded) jaw traps are still in use today.

1993= The Spanish flea was introduced to Australia to specifically reduce rabbit numbers in arid areas.

1996= The rabbit haemorrhagic disease (RHD) was officially released in New South Wales and has spread throughout the country. Studies have shown, however that many rabbits have developed a resistance against the disease.

Today= The aim is to develop a virus which causes sterility in rabbits rather than illness and death. Immunocontraception is believed to be a more humane way of controlling numbers.

In the meantime landowners can do a number of things on their properties such as: using machinery to destroy warrens, laying baits containing the poison sodium fluoroacetate (1080), fumigating warrens with carbon monoxide and chloropicrin, trapping, and shooting the rabbits that other methods have missed.

                                                         Bibliography

Department of the Environment, Water, Heritage and the Arts (DEWHA). (2010). Feral Animals in Australia. Retrieved Wednesday 21, 2010, from http://www.environment.gov.au/ biodiversity/invasive/feral/index.html.

Department of the Environment, Water, Heritage and the Arts (DEWHA). (2008). Background document for the threat abatement plan for competition and land degradation by rabbits, DEWHA, Canberra.

Foundation for Rabbit-Free Australia Inc. (2010). Why are Rabbits a Problem. Retrieved Wednesday 21, 2010, from http://www.rabbitfreeaustralia.org.au/rabbit_problem.html.

Williams, K., Parer, I., Coman, B., Burley, J. and Braysher, M. (1995) Managing Vertebrate Pests: Rabbits. Bureau of Resource Sciences and CSIRO Division of Wildlife and Ecology, Australian Government Publishing Service, Canberra.