At least 28 hihi chicks have been raised at Wanganui's Bushy Park forest sanctuary this season, Bushy Park Trust chairwoman Liz Tennet says.
There were 17 stitchbird chicks raised there last year, and there's evidence some of the young from that year have bred this season.
"The multiplication going on is wonderful," she said.
A further release of the endangered species was planned for this month, but has been postponed because rats were discovered in November.
They don't seem to have affected bird breeding, but a massive poisoning effort followed their discovery. It has reduced their number, and the number of mice.
More poisoning will be done as winter approaches. The rats will run out of natural forest food then and are more likely to take poison.
"We have a strong desire to get all of them, but we can't guarantee that."
When rat numbers are down, more hihi will be introduced, to increase the gene pool.
The Bushy Park wetlands and outdoor classroom, a Wanganui North Rotary Club project, will be finished soon. The Governor-General, Sir Jerry Mateparae, has agreed to open it on May 23.
The trust has not yet found a new person to lease the Bushy Park Homestead, but Ms Tennet hoped to make an announcement soon.
The rat incursion made it obvious that the 100ha forest sanctuary needs a full-time ranger, she said, and the trust had asked Horizons Regional Council for funding. The council's environment committee will be discussing that and visiting Bushy Park on April 15.
The Rotokare Scenic Reserve, of 230ha and 12km east of Eltham, has three staff. At least one one of them is funded by Taranaki Regional Council.
"We are the only sanctuary in the country without full-time staff, and the only one not supported by a full-time person via its regional council," Ms Tennet said.