Rabbit Problems in Australia

Rabbit problems in Australia

Rabbits in plague proportions

Rabbits in plague proportions

Rabbits, like most other pest species, were introduced when Europeans first settled in Australia. Rabbits were introduced from two main sources; the domesticated rabbit which provided early settlers with a ready source of meat, and the wild rabbit introduced later for hunting.

Thomas Austin is credited with releasing 24 wild rabbits at his Barwon Park property near Geelong in Victoria in 1859. This small population exploded to cover Victoria and New South Wales by 1886. By 1900, rabbits had reached the Northern Territory and Western Australia.

In some other areas, feral domesticated rabbits also established populations. Typically, these rabbits have different colourings compared to the wild rabbits released by Thomas Austin.

Environmental vandals

The rapid spread of the rabbit led to the destruction of large tracts of vegetation, leading to the extinction of many plant species. Loss of vegetation leads to soil erosion as the exposed soil is washed or blown away, removing valuable soil nutrients required for new plants to develop. This soil is typically deposited in waterways, causing siltation and destroying aquatic ecosystems.

This wanton destruction of habitat has contributed to the demise of many native marsupial species such as the bilby and the bandicoot as their feed sources were outstripped by marauding rabbits.

Competitors

Rabbits actively compete with domestic livestock and can alter pasture composition by selectively grazing on more palatable and nutritious plants. Seven to ten rabbits eat the equivalent of one adult sheep, and, during drought periods, rabbits can totally strip a landscape bare leaving no food for sheep, cattle or native animals.

Biological control agents

In the past, rabbit populations have been reduced enormously with the introduction of biological control vectors. In 1950, the myxomatosis virus initially wiped out between 95 and 100% of rabbits in some areas. However, rabbits recovered with the development of resistance in many populations. The introduction of Rabbit Haemorrhagic Disease or Rabbit Calicivirus (RHDV or RCD) also helped control populations, especially in arid areas, but again, rapid resistance to RCD has left rabbits as one of Australia's most formidable pests.

The Pest Animal Control Cooperative Research Centre recently estimated the direct cost of rabbits to the Australian economy at $113.11 million; however other estimations have suggested that the costs could be much higher at closer to $600 million.

Rabbit biology

Rabbits are territorial animals with a well defined hierarchy or 'pecking order'.

Rabbit territories and areas where they feed are commonly defined by piles of scats or faeces or by a scented exudate from glands under the chin.

Rabbits will rarely feed outside these designated areas unless seasonal feed shortages force them to forage further afield. This is one of the key determinants in the success of a baiting programme, as it is crucial to lay the trail where the rabbits are feeding. This area may not be where the warrens are located.

Breeding

A dominant male or 'buck' mates with most does within the group's territory. Dominant females can prevent lesser females in the group from breeding.

The gestation period of a rabbit is 28-30 days, with the average litter size between three and four kittens, depending on the age of the doe. Young does may have as few as two kittens, yet mature does may have eight or more. Five to six litters are possible in a good season.

Given excellent seasonal conditions, a mature doe is capable of mating again within hours of giving birth, while young does can start to breed at four months of age. In areas with less reliable rainfall and vegetation with poor nutritional value, breeding can be limited.

Dispersal

Juvenile rabbits will migrate from their parental territory to establish new territories of their own depending on seasonal conditions. The presence of unused warrens and harbour makes it easier for these rabbits to re-establish in an area.

Integrated rabbit control

For a rabbit control programme to be successful, an integrated approach is vital. Shooting, baiting or fumigating without follow-up warren or harbour destruction will leave ready-made homes for young migrating rabbits from surrounding areas.

Landholders should seek advice from their local government agency, licensed contractor or Landcare co-ordinator. These skilled staff can provide information about supplementary action for rabbit control including:

  • fumigation of warrens;
  • fencing;
  • destruction of warren systems;
  • removal of rabbit harbour; and
  • shooting.

The aim of any rabbit control programme should be to achieve local eradication and to prevent re-infiltration. One of the best approaches to achieve this is to work with your neighbours or local Landcare group. Group programmes achieve the best results and lowest long-term costs as rabbits are removed from a wider area. The wider the area of the group programme the better the chances of limiting rabbit re-infestation.

Ripping warrens and destroying harbour assist in long term rabbit control by making it difficult for rabbits to find ready made shelter.

Importance of achieving high levels of rabbit control

The success of any rabbit control programme in the long term depends on the level of control achieved at each step. Leaving just 10% of a rabbit population will result in the need to repeat the operation next season as the 10% of the initial population of rabbits will breed back to the pre-control population within 12 months if conditions are favourable.

As with most large-scale pest problems, best results will be achieved by co-ordinated approaches on neighbouring properties. Aim for 100% control and remove harbour to prevent re-establishment.

Local advice on rabbit control

Many of the agencies below employ experienced specialists who can assist with technical information on poisoning rabbits and advise on important additional rabbit control measures such as ripping of warrens, fumigation and fencing. Consult local staff when planning a rabbit control operation. They can also assist in co-ordinating group operations, advise on best practice procedures and may have access to bait laying equipment for larger programmes.

Victoria: Department of Primary Industries
Western Australia: Agriculture WA
Queensland: Natural Resources, Mines & Energy
South Australia: Natural Resources Management Boards
Tasmania: Primary Industries
ACT: Department of Environment
New South Wales: Rural Lands Protection Boards
All States: Local Landcare co-ordinators, rural merchant agronomists or licensed pest control contractors.


Animal Control Technologies
46-50 Freight Drive
Somerton, Victoria, 3062
Australia
Telephone +61 3 9308 9688
Fax +61 3 9308 9622

E-mail: enquiries@animalcontrol.com.au