More than a third of a Victoria penguin colony that helped inspire a movie has been slaughtered by foxes.
About 70 little penguins on Middle Island, 150m off the coast of Warrnambool, were found with broken necks by volunteers this week.
Warrnambool Coastcare Landcare Network chairman Bruce Campbell says he's devastated and is pointing the finger at foxes, which previously decimated the colony.
"A lot of the little penguins were killed but not eaten. They had their necks broken," he told AAP.
"It can be (characteristic) of foxes. They can get into a kill frenzy,"
Mr Campbell also said volunteers also found fox faeces on the island.
The little penguins were made famous by Oddball, the Maremma dog which spent two weeks on the island in 2006 protecting the penguins from predators.
This led to a permanent penguin protection program and a 2015 film about it starring Shane Jacobsen.
The program helped increase the penguin population from fewer than 10 in 2005 to about 180 before this week's attack.
The dogs visit the island intermittently, leaving their scent to deter predators.
"The dogs are never on the island continuously," Mr Campbell said.
"So during the breeding season the dogs are taken over ... and they might be left there overnight," he said.
Penguin protection has been stepped up following the attack.
