Environmental scientist Peter Frost said nesting success was high, with almost 78 per cent of known nests producing fledged young.
"Hatching success was equally high at 77 per cent, and fledging success was also high," Mr Frost said.
"The figures are higher than or equal to those recorded in 2013-14, when fewer females nested but which still produced outstanding results."
The results from both seasons are a testament to the suitability of Bushy Park for hihi, and press the case for the introduction of more birds to combat the effects of the initially small number of females from which many of the current population derive.
Mr Frost said a combination of the richness of biodiversity at the sanctuary, coupled with an extremely good fruiting season, produced enough food so that rats and mice were not forced to predate on hihi, their eggs and chicks.
"Up to now, at least, the rodents do not appear to have had a major impact on birds in general or hihi and saddlebacks in particular."
Hihi at Bushy Park appear to be thriving, suggesting that it is prime habitat for the birds.
The park itself is also thriving, with impressive interpretation signage telling the story of Bushy Park; its 3km of public walking tracks; seated areas around the hihi feeding stations, and now a boardwalk and all-weather amphitheatre that frames a stunning wetland.
Out of something so dire - the invasion of rats - has come a strengthening of purpose and relationships. Rat numbers will be monitored again this winter when food is scarce.
The boardwalk and new amphitheatre are part of a larger vision to promote education out of the classroom, says retired teacher and principal Robin Paul, of the Bushy Park Education Group.
"Outdoor education is an essential part of a child growing up, and with such an amazing place so close to Wanganui - family-friendly and accessible - there's no excuse for it not to be a favourite destination," Mr Paul said.
"The boardwalk and amphitheatre provides a safe learning environment for students to come and experience the birdlife, aquatic life, plant life, and the covered amphitheatre provides shelter from rain and sun throughout the year."
He says the values for children are an appreciation of our environment and to learn how to take care of our special places.
"We used to have a paid educator at Bushy Park, funded by the Ministry of Education, and one of our goals is to get that position reinstated."
The Education Group is also setting up education kits that can be used by teachers to "self-guide" around the forest and wetland. Five education stations will be set up with resources, such as nets so the children can scoop up aquatic life and look at it up close.
The wetlands project was spearheaded by Wanganui North Rotary, which sold 460 boardwalk planks to raise money for the project - and raised another $6000 for the amphitheatre.
Project director Cranleigh Chainey said: "We needed to raise money for the boardwalk, amphitheatre, native plantings and equipment shed. All up, it was a big job, and we couldn't have done it without the generosity of people and businesses who bought a plank, people like Wilf Emmett, the Eleanor Burgens Trust, and kind donations from Rotarians."
Sanctuary manager Mandy Brooke has taken charge of volunteers and a variety of other tasks which have lifted the professionalism and standard of operational activities.
The park is built on volunteer work, including the trust board, committee members, regular volunteers and experts who give their time and expertise. More than 1000 volunteer hours were recorded last month alone. Ms Brooke's vision is to see Bushy Park bustling with activity - school groups, families, volunteers and overseas visitors.
"I'd love everyone who comes here to learn about biodiversity and conservation, - what's precious, why it's precious, and what we can do outside sanctuaries to protect our environment."
She said relationships had flourished since the rat problem and DoC, Horizons Regional Council, the trust and committee members, volunteers, general public and business community had all contributed to eradicating rats and improving biodiversity controls and monitoring.
Perhaps one of the joys of Bushy Park is that it forces you to stop, listen, and engage in something far bigger than your own world. This stand of virgin lowland forest is thousands of years old, predating the arrival of humans. Its wetland is one of the remaining 3 per cent in the Wanganui-Rangitikei region.