ON THE WING
Against the odds, the little battler of the Derwent is maintaining a flipper-hold in what has been its home for millennia.
On a cruise around the river and wider estuary in mid-August, I was pleasantly surprised to count several rafts of little penguins on open water stretching from the shores of Tranmere to the south, to within sight of the zinc factory to the north.
The convenor of BirdLife Tasmania, Eric Woehler, confirms the penguins appear to be holding their own despite all that makes life difficult in an environment increasingly shaped by mankind, including frequent attacks by dogs on beaches where the penguins have their burrows.
Habitat loss, or the loss of undisturbed beaches where nesting burrows can be located above the tide line, is also a major reason for penguin decline over the past 30 to 50 years. Another major threat is the use of catch-all, unattended fishing nets. These nets present a death trap not only for penguins but other seabirds.
Penguins might be a vital component of Tasmania’s tourism but some selfish and uncaring tourists have had an unfortunate impact on numbers, not so much in the Derwent but at Bruny Island where there is still a sizeable penguin population.
At penguin-viewing sites on the Neck linking North and South Bruny island, tourists have been seen digging penguin chicks out of burrows so they can feature in “selfies” from the Apple Isle.
Dr Woehler said he suspected most of the birds I had seen from the deck of the Odalisque tourist vessel – resting up in the Derwent out of season from its regular operation at Port Davey in the South-West – were “prospecting” birds swimming the Derwent, looking for nesting sites.
“We have birds in burrows at the moment and I was on Bruny Island in mid-August, at the Neck, and there was plenty of evidence of penguins ashore,” he said.
Birdlife Tasmania has also seen a shift in the breeding phenology of penguins in South-East Tasmania. “The old paradigm of spring arrival, summer breeding and autumn moult is long gone,” Dr Woehler said.
“Now we are seeing winter and late-winter occupation and occasional breeding, late-spring and early-summer breeding, and even late-summer and early-autumn breeding, then moult.”
He also said penguin-breeding in Tasmania was increasingly meshing with the nesting period of mainland colonies where water temperatures were higher.
It all raises the question of whether global warming is starting to have an impact on penguin behaviour in Tasmania, with unknown consequences. Only time will tell.