Unseen but heard; rare bird research continues

A search for a shy and secretive species of wetland wading bird uncovered another rare bird in the region.

Now, researchers from a five-year, multi-agency study which began last year have installed listening devices in Otago wetlands in the hopes of hearing the birds’ calls this spring.

Otago Regional Council terrestrial ecologist Dr Scott Jarvie said the researchers were attempting to establish the numbers and distribution of the matuku-hūrepo (Australasian bittern) and pūweto (spotless crake) to understand the implications of wetland management practices on the species.

It was rare for anyone to see matuku-hūrepo as their numbers had greatly declined after the destruction of 90% of their wetland habitat, Dr Jarvie said.

The large, rare bird could blend into its surrounding habitat, which was typically difficult to access, he said.

"The distribution of matuku-hūrepo and how many individuals are in Otago is currently unknown.

"Anecdotally, there is only a small number of matuku-hūrepo in the region, which is why the next phase of surveying is so important," Dr Jarvie said.

In the first year of the study, matuku-hūrepo were recorded in the Catlins, the Sinclair Wetlands and near Queenstown.

Dunedin ornithologist Mary Thompson, of Birds New Zealand, said the research group would continue to scout locations in the hopes of turning up more bittern habitat.

During the birds’ breeding season, from August to December, adult males made a distinctive hollow-sounding call, similar to the sound made by blowing over the top of a bottle, Ms Thompson said.

Department of Conservation technical adviser Bruce McKinlay said any sightings of the bird should be reported.

Forest & Bird Tautuku restoration project manager Francesca Cunninghame said late last year the researchers found the pūweto in the Fleming wetland, within Forest & Bird’s Lenz Reserve, near Papatowai in the Clutha district.

It was the first report of the bird in Otago since 2015 and the first verified record of the bird in this part of Otago.

The researchers had subsequently heard pūweto on several occasions in the Fleming wetland, including a winter survey where the entire wetland was checked, she said.

A further survey was now planned for later in the year to try to get a better estimate of numbers, she said.

The research group includes members from the regional council, Birds New Zealand, Doc, the University of Otago and Forest & Bird.