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Environment

Bittern on the brink?

As a child walking down the road to catch the school bus, it was a regular treat to find a Bittern – frozen, large beak pointing skyward, almost taller than me, pretending it wasn’t there.
 |  The Informer  | 

Bittern – Shy, reclusive and extremely susceptible to human disturbance.

A generation later my niece and nephews enjoyed that same privilege as they too trod the gravel road to and from the bus.

That swamp still remains, largely intact in the embrace of the Whenuakite River as it curves around Harebridge Farm thanks to the husbandry of my brother Ralph and the family farmers before him.

Sadly, the same cannot be said for the rest of the river where in many places pastures reach right down to the waters’ edge. This is the situation reflected throughout New Zealand with more than ninety percent of our former wetlands lost, mostly to agriculture. Those which remain are in a sorry state through poor water quality and invasive species.

Australasian Bittern/Matuku-Hurepo is a flagship species for our wetlands although its streaked plumage, shy nature and cryptic behaviour mean that there is much we don’t know about its lifestyle.

What we do know and have known for years is that the population is in steady decline – now believed to be only 800 birds throughout New Zealand and described as Nationally Critical (DOC Threats Classification). This is the last step before extinction. It is hard to imagine that in the early 1900’s there are descriptions of flocks of Bittern 100 strong!

But it gets worse. Let me explain.

Drones with thermo-imaging cameras can now fly known Bittern hotspots on early spring mornings searching for the birds and their nests.

This seasons’ search of 1300ha (27 wetlands) in prime habitat in Bay of Plenty, Waikato, Northland and the Coromandel yielded 50 adult Bittern but only three Bittern nests.

Plenty of Pukeko and Harrier nests were also located. Two of the Bittern nests were in Bay of Plenty in an area that has been managed for Bittern for the last two decades.

The third was in a harbour on the Coromandel, a place which has the unenviable distinction of having lost at least four Bittern to road kill in the last twelve months.

In my own back yard, near Hot Water Beach, another Bittern lost its life on the road, just in this last month.

On one nest the female (who has sole charge) was observed off the nest for up to five hours at a time – presumably in search of food – leaving her offspring highly vulnerable.

Past survey methods have focussed on counting booming males, females are much more difficult to find, transmitter and track. This new survey technique strongly suggests the females are faring even worse than their males.

Starving chicks, as yet unable to fly, have been regularly handed in to DOC Tauranga having been discovered emaciated in harbourside gardens. It looks like chicks aren’t doing well either.

We don’t know for sure, but the anticipated lifespan of our Bittern is 10-11 years, so unlike Kakapo, we don’t have a long time to work this out.

A 2021 estimate has suggested a mere 125 pairs left.

I am grateful a chance conversation led me to the recent Coromandel Matuku – Bittern Workshop and opened my eyes to the decimation of this iconic bird of my childhood. Join me in turning the tide for our Matuku-Hurepo.

Our Bittern need help and they need it now – how can you help?

  1. Spread the word – share the link to this highly informative NZ Geo article on your FB page https://www.nzgeo.com/stories/the-grief-bird/
  2.  Advocate for an urgent national collaborative approach to Bittern management. Talk to your local District Council, Regional Council, local DOC office & Iwi representatives. Use any influence and contacts you have.
  3. Our Bittern are starving – farmers drains are now an important hunting habitat. Ideal conditions are clean clear water, 8-75cm deep (15cm best) with good fish passage to the sea i.e. no high culverts that bar fish movement. See this link for information on fish passage: https://www.doc.govt.nz/nature/habitats/freshwater/fish-passage-management/ – Advocate with any lowland farmers you know, publicise in any newsletters that reach lowland farmers. This link provides more detail on freshwater habitat restoration: https://www.doc.govt.nz/nature/habitats/freshwater/freshwater-habitat-restoration/
  4. Educate our tamariki – excellent resources are available for schools on the LOVE BITTERN! – AROHA MAI MATUKU_HUREPO! website at https://lovebittern.com/raising-awareness and scroll down to Childrens Resources.
  5. Support your local wetland restoration, weed and pest control groups as much as you are able.
  6. Support the newly minted Bittern Conservation Trust as they work to help species led conservation for the Australasian Bittern. They can be contacted via the LOVE BITTERN! website or follow them on their Facebook page.
  7. Full information and reports from the Coromandel Matuku-Hurepo workshop can be found at Predator Free Hauraki Coromandel Trust https://pfhc.nz/matuku-bittern-conservation-workshop-field-visit
  8. Watch Emma Williams from DOC present at the 2023 Australasian Bittern Conservation Summit. https:/www.youtube.com/watch?v=eRBcSwt0Hfg