Oddball, the maremma that proved dogs could be used to protect a Victorian penguin colony and inspired a movie in the process, has died aged 15.
She spent only two weeks on Middle Island but her short trip led to a permanent penguin-protection project being set up and a 2015 film being named after her.
"Old Oddball has gone to the big chook run in the sky and will rest in peace!" the Middle Island Maremma Project posted to Facebook on Wednesday.
About 150 metres offshore from Warrnambool and connected by a tidal sand bridge, Middle Island has been home to little penguins for decades.
Marauding foxes cut the island's population to fewer than 10 birds in 2005.
That led chicken farmer Alan Marsh, who had trained maremmas to protect his free-range chooks, to suggest applying the same tactic for the penguins.
The world-first project was so successful it attracted interest from as far as Italy and led to Shane Jacobson portraying the pioneering Mr Marsh in the 2015 family film Oddball.
Two dogs, Eudy and Tula, now spend five days a week on the island during breeding season.
The penguin population was estimated at 130 in 2015.