An Northland kiwi, known as Stripe, has been killed by a dog.
The adult male lived in the Purua Scenic Reserve, part of the Whangarei Kiwi Sanctuary.
Department of Conservation (Doc) staff were devastated by the death, said kiwi team ranger Miriam Ritchie.
The monitored bird was likely to have been killed by one of two dogs spotted wandering in the reserve last week, said Ms Ritchie.
"It's such a waste. Every kiwi killed by a dog is avoidable. Stripe was a great breeder and incubating two eggs, so his death has real consequences for the local population," she said.
Ranger Emma Craig said Stripe had fought off a stoat 10 years ago.
"I was checking his nest. When I got close I realised something was wrong as Stripe was stamping and growling within the burrow. I arrived in the middle of a stoat attack.
"An adult kiwi is more than capable of fighting off a stoat, so Stripe survived, but unfortunately both his eggs were lost."
Stripe has sat on many eggs, for the Bank of New Zealand Operation Nest Egg programme, as well as chicks for his own population and had been part of a sanctuary study since 1995.
"It's so frustrating...Northland kiwi can start breeding at three years, can produce up to six chicks per year, and can live for decades," she said.
Dog owners need to be responsible by keeping their dogs under control and away from kiwi, she said.
"New Zealanders are seen as world-leaders across many aspects of conservation, yet we don't control our dogs well enough to protect our national icon. It's embarrassing."
Kiwi can live for over 50 years, but in Northland the life expectancy was just 14 years due to dog attacks.
DOC are appealing for people to contact Environment Northland or their local Doc office if they spot wandering dogs in or near kiwi areas.
