A takahe chick hatched just before Christmas in Wellington is believed to have since died.
Conservation teams at the Zealandia eco-sanctuary this month announced breeding pair Nio and Orbel had set up a nest and suspected a chick had hatched just in time for the holidays.
But staff now say they're seeing no signs the couple are rearing a chick.
"We were excited but nervous, as young chicks are extremely vulnerable and Wellington had a very cold snap over Christmas," they said in a statement.
"We think that the torrential rain and cold weather on Christmas night and Boxing Day may have caused the chick to perish."
Nonetheless, they were hearted the breeding pair, who only arrived at the sanctuary in August, had settled in so quickly.
"We look forward to the next breeding season and having another chance."
The takahe was once thought to be extinct, but in 1948 it hit world headlines when Invercargill doctor Geoffrey Orbell rediscovered the bird high in the Murchison Mountains in Fiordland.
Takahe still exist in the wilds of the mountains, the Burwood Takahe Centre and 17 sanctuary sites.