The death of more than a dozen diving petrels discovered at Leisure Island is prompting a plea for cat owners to try keeping their felines inside after dark.

Members of the Mount Penguin Monitoring group have found 13 dead birds on Moturiki in the last week, including a pile of seven birds with their heads 'chewed off”.

Petrels found dead on Leisure Island.

Group co-ordinator Dave Richards says there will be more deaths they don't know about and believes a cat is responsible.

'Whether it is a feral cat or someone's pet, we do not know.

'This is not an anti-cat message – just a request for good pet owner responsibility. We have a very special place here.”

Dogs are already banned from Leisure Island and Dave is asking people to try keeping their cats locked inside at night.

Rabbit Island's (Motuotau) diving petrel population was devastated in 2002 after a stoat invaded the island killing nearly 100 birds, says Dave.

The population has been recovering since.

Dave says they find dead birds every year but this year is particularly bad.

Diving petrels make for easy prey as they are unable to escape quickly from predators.

They have no flee response due to evolving in a predator free New Zealand, says Dave.

'When nesting, they land on the ground exhausted from flying and sit there recovering and because of the lack of predatory response do not see other animals as being threats.

'This is why most New Zealand seabirds have been wiped out on the New Zealand mainland. We are very lucky here in Tauranga - we still have a few sites where they still land and attempt to nest.”

If anyone finds a dead petrel, please contact Dave on 021 719 622.