Shy and secretive, our little penguins are usually out of sight and out of mind until tragedy befalls their colonies.
They only come to notice, hitting the headlines, when they are the victim of dog attacks although one celebrated penguin hit the news last year by trying to gain access to a Hobart Waterfront pub. The penguin was found on the steps of the main bar of the Post House Hotel after apparently coming ashore at Brook St Pier.
Putting aside amusing penguin antics, little penguins are increasingly threatened by human activity, climate change and habitat loss. But in Tasmania, dogs are the biggest killers, threatening to wipe out entire colonies within just a few years.
A new study looks at how dog attacks of different frequencies and intensity can impact small, medium and large colonies by using data on penguin mortalities collected since the 1980s.
There were 71 recorded “mortality events” involving little penguins in Tasmania between 1980 and 2020, and of those, 55 were listed as dog attacks or suspected dog attacks and accounted for 887 penguin deaths. A mortality event is described as an incident in which one or more penguins are reported dead.
It is thought that while some of these attacks were by roaming or feral dogs, the majority were pet dogs that had escaped or were not on a lead while being exercised.
When the researchers used population modelling, they found that even low levels of dog attacks – killing 15 to 20 birds every three to five years – were capable of wiping out small colonies over time.
The same modelling revealed that if only 10 per cent of penguins in medium-sized colonies were killed by dogs in frequent attacks, those colonies would also be at risk of population collapse, potentially becoming extinct within a decade.
Even in large colonies which support more than 500 penguins, extinction was hastened by dog attacks. Being flightless and spending their nights in colonies along the coastline, adult penguins were particularly susceptible to attacks by dogs at night.
While improved monitoring will continue to help scientists identify potential causes of little penguin population declines, it’s hoped the study will highlight how individual dog owners can make a difference.
In 2019, the Tasmanian government introduced tougher penalties for dog owners whose animals kill “sensitive wildlife” in declared areas.
Under the current laws, dog owners can receive a maximum fine of $5,040 if their dog injures or kills sensitive wildlife, and the animal could also be put down.
Little penguins (Eudyptula minor) are the smallest of all penguins and breed across southern Australia, with the majority of colonies found in Tasmania. In the Derwent there is a declining population of less than 200 birds.
The penguin study was led by the CSIRO, with contributions by BirdLife Tasmania and Institute for Marine and Antarctic Studies.