The Kakapo Recovery team is considering removing a male bird from its breeding programme after the deaths of several young kakapo.
A three-year-old kakapo named Rooster died last week, the fifth fatality since September last year.
Of the six young kakapo to die recently, four were fathered by a bird named Basil on Anchor Island in Fiordland.
Kakapo Recovery programme manager Deidre Vercoe Scott says the team is investigating the cause of the deaths, including whether there is a link with Basil's genetics.
There is a very low variation in the critically endangered species' gene pool.
There are now just 126 kakapo in the world, down from 131 in June last year.
The main kakapo population is on Whenua Hou/Codfish Island, off Stewart Island.