Bay’s blue duck population recovering
The rare native whio, or blue duck, has returned to its habitat in Hawke’s Bay following a disaster which hit the population nearly six years ago.
Snowstorms and floods in August 2016 around Maungataniwha reduced the whio population around the Waiau and Te Hoe rivers from 19 breeding pairs to just four.
An annual survey by the Department of Conservation and the Forest Lifeforce Restoration Trust in November 2021 found 16 breeding pairs in the area, close to pre-storm levels for the first time in five and a half years.
The survey focuses on breeding pairs to give an indication of future population size, so it does not include the number of single birds or juveniles found.
Forest Lifeforce Restoration Trust’s forest manager Pete Shaw said last year’s survey showed whio populations on all waterways had recovered or even improved slightly, except for a small section of the Waiau river.
“We suspect that ongoing and highly effective predator control at Ngatapa and Pohokura stations, along with trapping at Maungataniwha funded by the trust, has a lot to do with this recovery,” he said.
“As has the success of the joint DoC and Ngati Whare recovery work in the Whirinaki Te Pua O Tane Forest.”
According to DoC, there are fewer than 3000 whio left across the whole of New Zealand and the species is considered threatened, nationally vulnerable or endangered.
Whio are only found in New Zealand, and are also known for appearing on our $10 bills.
They’re known as an indicator species because they only live on clean, fast-flowing rivers, which means the amount of whio can be indicative of the health of a river and of how well other species are doing in an area.
The whio survey at Maungataniwha is done at the first and last hours of daylight, when the whio are most active, during the breeding season.
It involves walking, rafting and tubing the streams, looking and listening for whio and looking for signs such as faeces and calls, sometimes with a specially-trained whio detecting dog.