Rabbits are small placental mammals found in several parts of the world. There were no rabbits in Australia until European settlement in 1788.
First Rabbits in Australia
The first rabbits, numbering five, arrived in Australia with the First Fleet in 1788. Consequently there are occasional written references to the presence of rabbits in Tasmania and New South Wales by the early 1800s. Initially they were bred in confined enclosures for food and appear to have had no noticeable impact on the local environment.
Thomas Austin of Barwon Park of Winchelsea in Victoria was a pioneer landowner in the area. Like many other early settlers he brought numerous animals from his native country to Australia. Austin was also a member of the local Acclimatisation Society which encouraged the introduction of foreign animals and plants into Australia.
In 1859 Austin, who had been an avid hunter back in his homeland of England, imported seventy-two partridges, some sparrows, twelve grey rabbits, five hares and some domestic rabbits so that he could continue his hunting hobby in Australia.
He built well-fenced enclosures on his vast property at Winchelsea to keep the rabbits in and even hired a game keeper to look after his animals. Much to his surprise and praise from his neighbours his rabbits multiplied exponentially. In just six years his rabbit herd had increased from a dozen or so animals to over 20,000.
How Rabbits in Australia became Feral?
Given the massive increase in the rabbit population at Barwon Park it was only a matter of time before some of them escaped into the wild. There a number of theories as to how this may have happened. The first is that the Barwon River which flowed next to the Austin's property, flooded and the rabbit enclosures fences were washed away and the rabbits escaped. Another is that local people cut holes in the rabbit fences to illegally catch the rabbits which were on the property. The rabbits may have escaped through these opening or may even have been encouraged to escape by the local people so they could catch them more easily elsewhere. The final theory is that when the Duke of Edinburgh visited Barwon Park on the 5th of December 1867 as the guest of the wealthy Mr Austin, a hole was cut in the fence and rabbits chased out of the hole so that there would be an unbelievable spectacle of rabbits everywhere when the Duke went rabbit shooting. The local newspapers report that the Duke stayed as a guest of the Austin's at Barwon Park and went hunting that afternoon. Over 1,000 rabbits were shot of which the Duke is credited with shooting 416. He went hunting again the following morning for three hours and shot another 86. This is probably the most likely explanation of the rabbit plague that followed because a large number of rabbits were released allowing them to establish themselves in Australia. (The newspaper engraving shows the rabbit fence on the right).
How did Rabbits in Australia become Invasive?
The rabbits that escaped that day multiplied rapidly in Australian wilderness which was similar to their original places of origin in Spain and Portugal (The ancient Romans took them all over Europe from there).
Within just twenty years they had reached Queensland over 1,500 kilometres away. By 1910 they had spread to their present range, which is most of Australia except the wet tropics.
It is estimated that there are about 300 million rabbits in Australia. (See what they mean when they say "breed like rabbits").
Why Are Rabbits a Pest in Australia?
Rabbits have been declared the number one pest in Australia because to the serious damage they are doing to the Australian ecosystem.
Their major impacts are:
• Rabbits overgraze the land to a point that native plants die leading to wide-scale extinction of native plants.
• The loss of native plants contribute to the decline and in some case the extinction of native animals such as the bilby and the bandicoot.
• Loss of vegetation also results in soil erosion. The exposed soil is easily carried away by wind and rain leaving it degraded and unsuitable for new plant growth.
Soil washed away by rain typically ends up deposited in creeks, streams and rivers disrupting the aquatic ecosystem of these waterways.
• Rabbits also eat pastures put down by farmers for their sheep and cattle flocks.
• During droughts, when foods is scarce, rabbits dig up and eat the roots of plants thereby killing them.
• Rabbits also threaten some of native burrowing animals, such as the bilby and the burrowing bettong, by evicting them and moving into their burrows.
Rabbit Control in Australia?
From as early as 1887, just twenty years after the rabbit was first released at Barwon Park, rabbit numbers had grown to plague proportions in Victoria and New South Wales. Western Australians were so alarmed that they built a rabbit-proof fence 1,800 kilometres long to protect their state from a rabbit invasion. This didn't really work because rabbits jumped over the fence, borrowed under it or humans left gates open letting them in. Other early methods of controlling the rabbit populations was shooting, poisoning and digging up burrows.
By 1950 the rabbit population in Australia was estimated to be over 600 million. There were 80 rabbits for every single person living in Australia at the time. In this year the myxoma virus was deliberately released into the wild rabbit population resulting in a rapid decline to about 100 million. Initially mosquitoes were the key transmitters of the disease but they were unsuitable for the drier parts of Australia so the European and Spanish fleas were brought to Australia to spread the virus more widely. Some rabbits were resistant to the virus and numbers again started to increase. By 1991 there were an estimated 300 million rabbits in Australia. In 1995 Australian scientists were testing the calicivirus which accidentally escaped and fortunately has been doing its job killing only rabbits.