Fairy penguins mauled on Sydney beaches

Four fairy penguins have been fatally mauled by a dog on Sydney's northern beaches, devastating local volunteers who work to protect them.

Manly Environment Centre volunteer Angelika Treichler said the endangered penguins were found with smashed skulls on a private beach in Manly on Friday.

"We haven't got the autopsy results yet, but it looks like they were mauled ... by one dog," Ms Treichler told AAP.

"We've had one dog mauling eight all at once a few years back on the same little private beach."

She said dogs were banned from the area, which is home to the only mainland colony of the penguins in NSW.

Volunteers work vigilantly to protect the 65 breeding pairs in the area, she said.

"We're all working every night ... at Manly Wharf protecting the penguins.

"It's heartbreaking when you look after the penguins.

"I've been looking after them for five years now and every little penguin counts and four in one go, I still can't believe it."

© AAP 2009