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Mohua Charitable Trust founder Nigel Babbage said the number of birds counted in a recent survey was a great satisfaction.
The survey in the Makarora and Young valleys during the spring recorded 66 mohua as heard or seen.
Department of Conservation ranger Flo Gaud said that was more than expected.
''The numbers could be even higher but unfortunately, due to a cold, rainy period during the survey, the birds could have been reluctant to sing or come out.
''We always knew we had a small remnant population of the birds but this survey gives us a much more accurate picture of their numbers and location.''
Doc, the trust and the Central Otago-Lakes Forest and Bird Protection Society have been operating 200 predator traps along the Haast Highway and near the Bridal, Blue Pool and Blue Young Link tracks.
In 2012, 313 stoats and 109 rats were caught.
Ms Gaud said the next step would be to source funding to prepare a rat control programme.
The once widely spread mohua nest in holes in trees and are particularly vulnerable to predators.