The bird on the back of your $10 note is fighting back from near-extinction with 56 ducklings counted by DOC rangers in a record breeding year.

The blue duck or whio is rarer than the kiwi, with an estimated nationwide population of fewer than 3000 birds.

However, the species is rejuvenating after a record breeding year, boosting the whio population on Mt Taranaki.

DOC rangers released three more young male ducks into the Waipuku Stream on Monday, capping off the 56 ducklings counted within the eight surveyed rivers.

The whio was labelled "functionally extinct" in 1945 after stoats and rats devastated the population but intensive conservation programmes have brought the species back from the dead.

The environmental project Taranaki Mounga has extended the stoat trapping network around Mt Taranaki in the last year and a partnership between Genesis Energy and DOC has enabled the whio population to build up to 33 pairs.

"Whio are particularly vulnerable during nesting time so it's fantastic to hear we have a recordnumber of chicks on Mt Taranaki this breeding season," Taranaki Mounga Project Manager Sean Zieltjes says.

Whio only live on fast-flowing rivers where there is a good supply of underwater insects so they are an important indicator of ecosystem health.