Residents and environmentalists want little blue penguins around Wellington to be safe while nesting.

Dog owners should be responsible for helping to save little blue penguin populations in urban areas, an environmentalist says after an adult bird was found dead at a Wellington reserve.

Te Motu Kairangi-Miramar Ecological founder Joakim Liman called for safer penguin nesting sites after he found the carcass of the dead kororā, or little blue penguin, sprawled on its back and infested with maggots, at a regular nesting site in Oruaiti Reserve, on the Miramar Peninsula.

He said the penguin was next to the walking path that runs between Worser Bay and Breaker Bay, at the entrance to Wellington Harbour, and he believed the most likely culprit was a dog.

JESSICA LONG/STUFF Breaker Bay, where little blue penguins have been known to nest alongside homes.

"We didn't know if this was a dog but it is a most common cause of death. [Penguins] have no defence against a dog.

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"Some are having chicks that have hatched, but if the parent dies it means we're losing the whole clutch of eggs as well."

Little blue penguins lay up to two eggs between July and October, which are incubated for about 40 days before the chicks hatch, between September and December.

The Seatoun penguin's death coincides with calls from a Breaker Bay resident and dog owner Raymond Morgan for Wellington City Council to promote little blue penguin aversion training for dogs and pet owners in the region.

People might not realise little blue penguins nested on walking tracks, because they had "a secret lifestyle".

"You're more likely to smell or hear them ... there are penguins all over the place.

"They have to live alongside people dogs, cats, hedgehogs, rats, stoats, so of course the numbers are less, but they're still here."

A better understanding of their habits, nesting sites and knowledge on how to protect species living in the area could be the difference between building populations or demolishing them, he said.

"We can happily live with penguins so long as we know what they need."