The Department of Conservation says mohua numbers have risen more than 30-fold and overall native bird numbers have doubled in the 21 years since monitoring began in 1998.
Doc principal science adviser Colin O'Donnell said mohua had gone from just 14 birds to 444 counted in the Landsborough area last November.
Other birds such as kaka, fantail, and kereru were stable. However, silvereye and the migratory long-tailed cuckoo had declined.
For silvereye this could be due to greater competition for nectar from the more aggressive tui and bellbird, Doc said.
Predator control began in the Landsborough Valley in 1994. Since then, Doc has done valley-wide trapping, and six aerial 1080 poisoning operations.
The Landsborough is a priority for aerial 1080 poisoning this year.
