A pair of wood ducks catching the last rays of a dying winter sun had the shock of their lives when a duck-billed platypus leapt from the water in the Cascade Gardens and joined them.
The ducks were resting on the flat concrete sluice which carries the Hobart Rivulet to the boulder trap catching rocks and tree trunks before they can block the watercourse closer to the central city.
The platypus had been swimming and diving in the substantial concrete-lined trap before taking a time-out of its own. Watched nervously by the ducks after it hauled itself from the water, it then rolled on its back and scratched the fur on its cream-coloured belly, contrasting with the rich-brown fur on the rest of its body.
The ducks were not the only witnesses to the platypus’ antics. “Platypus tourists” had gathered, a party of about 20 Chinese birdwatchers among them, for what has become a popular Hobart spectacle.
The presence of platypus in the river, swimming as far as Molle St in the CBD, have been known to locals from the time the boulder trap was built in the 1960s but the screening of an ABC documentary The Platypus Guardian, featuring platypus champion Pete Walsh, firmly put the rivulet on the map for both national and international tourism.
Recognising the appeal, the Hobart Council has installed an information panel on the bridge above the dam holding the boulder trap’s waters. As the wording says, the designers of the trap could never have envisaged all those years ago that it would prove perfect habitat for platypus, creating the deepest pool of water along the entire rivulet.
Along with rocks and trees, the dam traps a large amount of organic matter, the building block of the ecosystem that provides sustenance for the monotremes.
Sometimes more than one platypus can be seen. They are often in view because, as the information panel explains, they hunt food for 12 to 14 hours each day, diving up to 2000 times, dining mostly on water bugs but they also eat worms and yabbies.
The council has made great strides in recent years to keep the rivulet clear of rubbish like rubber bands and plastics that can ensnare the platypus, much of it coming from the Hobart tip.
In response to the powerful community campaign to protect the platypus, the council has installed what it terms a gross pollutant trap. The 45-tonne, $500,000 underground installation can hold nearly 10 cubic metres of litter, far in excess of the existing downstream ”sock” which has a tenth of the capacity.
The investment aims to make Hobart the “platypus capital of Australia” and ensure the lovable creatures a long and healthy life in the city.
* Platypus tours led by Pete Walsh can be booked through the council.