Spring weather in September is perfect for sitting near a river with a picnic and a good book.
In Kangaroo Valley it is natural to watch for platypus while there. The Australian
Conservation Foundation and the University of NSW hope that you will record any platypus
you see, or don’t see, in their Platy-project platypus sighting database to help researchers
learn where platypus are, or are no longer. The project is here: https://www.acf.org.au/platy-
project Researchers at UNSW and ACF have joined forces in the Platy-project to raise awareness
around the decline in number of these extraordinary creatures whilst, at the same time
increasing knowledge about their habitat and spread around Australia.
The project measures historic sightings against present sightings to determine where
platypuses have or have not survived and in what numbers. A map in the project indicates
locations of previous sightings around Australia, and colour codes indicate how recent those
sightings have been (a few years or a decade or decades).
During September it is hoped that people can go and spend time at those places to see if there
are still platypuses there. In addition, any places where platypus sightings have not been
previously recorded but where they are now present would be very useful information.
Details of how to participate in the Platy-project are on the website.
Researchers have found historic records of platypus populations in numbers not seen now.
For instance the attached newspaper cutting records a platypus sighting in 1859 in which
about a hundred platypuses could be seen moving together along the Gwydir River.
Numerical data from the fur trade suggest that platypuses were abundant at the end of the
19th century. A furrier reported selling more than 29,000 skins before the first world
war. Sportsmen reportedly shot hundreds and sometimes thousands of platypuses, given that
each garment or rug normally required more than 50 platypus skins.
Amongst historical records from digitised newspapers is a report from 1865 stating that 16 to
18 platypuses were shot “in a few hours” in the Shoalhaven River.
Even as recently as 1954 there is a report from the Gloucester River of 40 platypuses being
seen “at once”.
There is a 40 year study of platypus in the Shoalhaven River by UNSW researchers which is
interesting to read as it tracks populations in the river over time. It is here:
https://www.nature.com/articles/srep16073
Around Australia land clearing has contributed to a decrease of over 20% in platypus
populations in the past 20 years. Infrastructure such as roads and dams threaten platypuses by
restricting their natural movement patterns. Roads act as barriers, making it difficult for
platypuses to move between waterways.
Other hazards include extreme weather events and climate change, runoff silt, fertilisers and
other chemicals from pastures which cover the floor of the river where platypus find their food, litter that has drifted into waterways especially plastics and loops and hair ties that
entangle platypus, and fishing lines, nets and yabby traps that drown them.
Platypus mostly inhabit rivers with steep or overhanging banks with friable soil which allows
them to build burrows.
Their burrows can extend 30 metres from the river, and a researcher recently found that
nesting burrows are built at a depth of only about 30 cm from the land surface, making them
vulnerable to cattle feet and to any digging activities within 30 metres of the creek during
nesting season (which is October to February). If the nesting burrow is damaged from above
the platypus cannot reach her puggle. So care must be taken to keep livestock and digging
activities more than 30 metres away from river edges during nesting months.
Platypuses are mostly nocturnal. During the day they sleep in the chambers at the end of the
riverbank burrows. At dusk they emerge to search the river bottom for food, sometimes
hunting for 10 to 12 hours a night.
While underwater foraging for food, they can tightly close their eyes, ears and nostrils. In this
way they hunt for prey underwater for 30 to 140 seconds at a time, using electroreceptors on
their bill to detect electrical signals given off by prey. Yet they’re awkward on land, walking
on their knuckles to protect their webbing.
They’re completely carnivorous (meat-eating) and mostly eat invertebrates: swimming
beetles and waterbugs, insect larvae, tadpoles, worms, snails and shrimp. They scoop up
gravel and dirt along with their prey, store it in their cheek-pouches, and bring it all to the
surface to eat.
Things we can do to help our platypus include:
*preserve native vegetation near creeks and wetlands
*avoid draining wetlands
*rest areas of native vegetation from grazing
*avoid removing snags (fallen logs) from rivers and waterways
*replant trees and understorey plants to stabilise stream banks
*take care with disposal of pesticides, herbicides and other chemicals to prevent leakage into
creeks, wetlands and farm dams
*avoid fishing with gill nets and drum nets because they will drown animals
*avoid constructing dams with deep still water.
And it will help our platypus if we participate in the Platy-project and monitor how they are
going, especially after the recent floods and the fires a few years ago, and help strengthen the
case for the protection they need.
Kate Watson
For the Kangaroo Valley Environment Group