The widespread Melbourne floods of early 2011 have likely lead to the sharp drop in platypus numbers recently identified by cesar. Future platypus surveys will be crucial in determining the flood response and recovery of platypus numbers.
As part of the long term Melbourne Water Urban Platypus Program (MWUPP), cesar conducts intensive biannual platypus surveys.
The autumn 2011 surveys showed the lowest catch rates every yielded through the MWUPP and the floods could have been a major factor.
Floods can potentially drown animals in burrows, increase energy required to forage in strong currents, and physically displace individuals from their home range.
In addition, at the time of the 2011 floods, the current season of young platypuses would have still been confined to their maternal burrows and extremely vulnerable to drowning, or being washed out of burrows where they would be unable to forage for themselves.
The platypus’s food supply is also likely to have been affected, with aquatic invertebrates swept from the bottom of streams.
Periods of drought as well as relieving rainfall appear to have also affected platypus numbers in the past.
Following extended drought conditions in southeastern Australia, platypus surveys over the past 15 years revealed declining numbers around Melbourne (link to ‘Pop trends’ story).
Surveys conducted in spring 2010 indicated an increase in platypus catch rates at many sites throughout Melbourne’s catchments, coinciding with increased rainfall over the previous 12 months (see: End of the drought for our parched platypuses).
The next season of surveys will be conducted in Spring 2011.
What to do if you find a sick and injured platypus
If you find a sick or injured platypus, DO NOT pick it up.
Although not naturally aggressive, injured or distressed animals can cause injuries to rescuers. Male platypuses have venomous spurs on their hind legs, which can cause excruciating pain and swelling.
Contact a local wildlife carer, Melbourne Zoo or Healesville Sanctuary and pass on the details of the platypus.
If the animal appears alert and not seriously injured, the best course of action will be the return of the animal to the nearest body of water.
Platypuses do not handle captivity well and can become overly stressed.
If it is necessary to handle the platypus (i.e to move out of harms way), the appropriate method is to grasp firmly by the end of the tail.
Place the injured animal in a secure box or cloth bag (pillowcase) and keep in a cool, quiet location.
Importantly, DO NOT place near a heater. Due to their lower body temperature, platypuses can easily become heat-stressed.
Contact a local veterinarian, Melbourne Zoo or Healesville Sanctuary as soon as possible.