Victoria University researchers have found that Australia's wild native ducks may be at risk of extinction as they increasingly breed with domestic ducks.
Research Fellows Dr Patrick-Jean Guay and Dr Randall Robinson of VU's Institute of Sustainability and Innovation found native Pacific Black Ducks appear destined to follow a similar fate in Australia as they have in New Zealand, where they are now likely extinct in their pure form.
Their nemesis is the domestic duck, or Mallard, which mates with wild ducks and creates cross-bred populations.
Dr Guay said hybridisation not only represents a threat to biodiversity - the life-sustaining dispersal of species across the planet - but Mallards and their hybrid offspring can become a nuisance since they are more aggressive, more tolerant of humans, and can invade urban habitat.
On Lord Howe Island, for example, an increasing number of Mallards and their hybrids have caused extensive beach fouling, and tourists now tend to avoid those areas.
During a three-year study, the researchers aim to determine the genetic integrity of Australia's native duck populations by collecting DNA samples of ducks from hunters.
Once the extent of the problem is exposed, recommendations to manage Mallards will be submitted to the nation's wildlife agencies. The sampling has already started in Tasmania and parts of Victoria.
"In New Zealand, it took less than 100 years from when the first Mallards were introduced from Europe and North America for wild Pacific Black Ducks to reach the brink of extinction," he said.
"Most ducks in New Zealand now are hybrids between Mallards and Black Ducks," he said.
Dr Guay said it was important for people not to release domestic ducks into the wild, nor to feed those in urban settings. Domestic ducks can be distinguished from wild ducks by their larger size, their orange legs and their yellow (males) or orange (females) bills. Their plumage ranges from white to black and all shades in between. The native Pacific Black Duck is smaller and has olive legs and a dark grey bill. It is mostly brown and has a black stripe through its eye.
Dr Patrick-Jean Guay, Research Fellow
School of Engineering and Science/ Institute for Sustainability and Innovation, Victoria University
Ph: (03) 9919-2993; Mobile: 0439 309 133.
Ann Marie Angebrandt, Media Officer
Marketing and Communications Department, Victoria University
Ph: (03) 9919-5487; Mobile: 0403 556 001.