By Andy Glaser, DOC Ranger and Whio Recovery Group Leader
The whio, or blue duck, appears on our $10 note and the wild rivers of the back country, and not many places in between. As such, few New Zealanders know whio exist, and most will have never seen or heard one. With just 3,000 left in the wild, a partnership between Genesis and DOC called Whio Forever was created in 2011 to protect and grow the population of this national taonga. In this ‘Whio Journal’, Whio Recovery Group Leader, Andy Glaser, explains what Alert Levels 4 & 3 mean for whio survival.
Since our last journal entry, our country has gone through unprecedented change to break the cycle of COVID-19 transmission. As we begin to emerge out the other side into Alert Level 3, some of you might be feeling anxious about how these measures will impact whio. Like you, most DOC staff are required to stay home to stop the spread of COVID-19 and save lives. I want to reassure you that our achievements over the past nine years have put whio in a good position to withstand this moment in time.
But firstly, what are whio up to at this time of year?
Luckily, whio have finished breeding and moulting, allowing them to be more mobile. The fast-flowing waters they live in offer a natural defence and quick get-away from predators who are not as adept at swimming in these waters. Meanwhile, juvenile whio fledglings (young birds that have grown the feathers necessary for flight) will be dispersing and starting to find new territories up to 80 km away from where they were born.
Why are predator-control programmes so important for whio?
Studies undertaken in Te Urewera, Fiordland and Wangapeka, identify stoats as the major contributor to whio decline. These studies show we can lose up to 91% of nests in unprotected environments. Understandably, this severely impacts breeding productivity and the addition of juveniles back into the population to sustain long-term survival.
A juvenile dispersal-and-survival study in Ruahine found that 64% of fledged juveniles perish in the first two years in unprotected environments. To make matters worse, 46% of adult females can be lost through the breeding and moult period (December – February). While they moult (re-grow their feathers), whio are flightless and retreat up-side streams. They lose the water for defence and literally become ‘sitting ducks’. The loss of breeding stock is an even greater tragedy in the fight for survival.
These combined effects on unmanaged whio populations paints a grim story of their decline and the threats that they face on a regular basis. Whio are therefore ‘conservation-dependent’, meaning they need us to manage these pests for their continued survival.
Unlike other threatened species that can be put on predator-free offshore islands for their security, whio can only be protected on the mainland, as they only live on fast-moving rivers found in the North and South Islands. This requires a scale of management like no other species. Therefore, a major component of the Whio Recovery Plan is to target predators within our ‘Security and Recovery Sites’ with trapping networks and Tiakina Nga Manu (1080 aerial operations).
We check our trapping systems monthly before winter sets in and stoat numbers decline. This means our trapping networks were checked and reset in March this year (before lockdown) and have been functioning during Alert Level 4 to minimise the impacts of stoats on whio. At Alert Level 3, backcountry areas (which inclue our Security and Recovery Sites) are still off limits, but as soon as Alert Levels permit, we will be out in those hills to check traps with a vengeance!
Hot on the heels of a mega-mast event, whio have also been a priority for protection in our Tiakina Nga Manu operations. This offers catchment-scale protection that whio require. Success of this scale of operation is demonstrated in a study in Wangapeka after a Tiakina Nga Manu aerial operation, which documented a 92% nesting success in Year 1, 53% nesting success in Year 2 and 33% nesting success in Year 3. This study supports the residual benefits of aerial 1080 operations, for protecting whio and building a robustness in these populations.
Through amazing collective efforts around the country, we have seen our whio population grow from 298 pairs in 2011 to more than 725 pairs in 2019. This has been primarily through partnership with Genesis, who have contributed more than $4.5M of funding over the last 9 years. Their support of the Whio Recovery Plan, through the Whio Forever programme, has enabled the installation of more than 5000 traps that cover approximately 1500 km river. This, in conjunction with the Tiakina Nga Manu operations, has left whio in good stead going forward.
However, the backbone behind all this work is the people. It is our dedicated and hard-working volunteers, community groups, partners, contractors, iwi and DOC staff who have made Whio Forever what it is today. It is this same collective spirit uniting us as a nation at the moment. Together, we are stronger. We can protect and restore New Zealand’s incredible biodiversity, which faces challenges every day.
For now, I’d like to leave you with an adapted phrase I like to use which seems very fitting at this testing time: “Be like a whio and go with the flow. Keep calm on the surface, but paddle like the devil underneath”.