Source: Department of Conservation
‘Boom-chains’ from hide-and-seek legends with stabby beaks – matuku-hūrepo/Australasian bittern have a vocabulary all of their own, finds DOC Communication and Media advisor Krysia Nowak.
We hear the booms as soon as we arrive.
Deep, resounding booms carrying across part of the Te Mātāpuna wetland south of Lake Taupō. A bit like the sound you make when you blow across the top of a glass bottle.
These booms are the reason we are here. Usually silent stalkers in swamps, male matuku-hūrepo/Australasian bittern make an exception around breeding season – spring.
Believed to be an attempt to attract females, male bittern can spend hours at dawn and dusk producing this eerie sound.
We want them to succeed. Our native Australasian bittern are critically endangered due to habitat loss, predation, and disturbance.
Central Plateau Department of Conservation staff are monitoring these wetlands with the help of Project Tongariro volunteers. Four of us are here tonight, sitting warm and comfortable, observing the stunning sunset across a sea of raupō/bullrush. It’s cushy for fieldwork, at least until the mosquitos arrive.
First, we hear three faint booms some distance away. Then behind us, a new bird, a little closer, two booms. They’re probably birds competing with each other.
A new bird draws in a gasping breath in preparation, producing a massive four booms with a laboured gasp between. We have a new ‘boom-chain’ champion.
It’s called a boom-chain – a call sequence male bitterns bust out on the regular during spring evenings. Usually, the same bird will consistently give off the same number each time they call.
We listen. The booms become more regular as the male birds continue what seems to be a competition. Pencils scratch against our clipboards as we write the time, number of calls, bearing, and approximate distance of the birds.
Bittern booming, love looming?
Our boom-chain champion sounds very close. We can’t hear the wheezing in-breath of the other males.
One of our number stands up excitedly.
“I can see it!”
“I can see two!”
Suddenly we’re all standing. Peering across the raupō in the gloom of dusk at two slightly darker patches perched atop the rushes. We share the binoculars around.
Watching closely, one of the bittern seems extremely interested each time one of the boom-chains is heard. “Up-periscope” is our description.
The bittern flies, closely followed by the other. A suspicion blooms. Have we been watching a male and a female?
Bittern are hide-and-seek legends, usually blending seamlessly into their surroundings, so I can only describe the excitement we felt at this point to be “unintelligible glee”.
Monitoring
Knowledge is power, the more we know, the better we can protect these taonga.
Currently, we’re only monitoring males. The females are largely silent, presumably listening for their ideal mate.
In coming years the Department of Conservation staff here hope to use a thermal imaging drone to detect the females on the nest, but until then we’re limited by what we can hear. We don’t know how many of these males pair up with a female or remain bachelors.
We do know numbers of males have been pretty consistent around here for the last few years. The extensive wetland probably supports plenty of ideal prey species like fish, frogs, and invertebrates. Bittern soundlessly hunt these, striking with their stabby beak (non-technical term). If you ever meet a bittern, do not engage the stabby beak!
The struggle and the saving of matuku-hūrepo
You may have guessed by now I have a little bit of a soft spot for these statuesque birds. I was almost in tears when our team had to pick one up from the road once, hit by a car. It’s not their fault we build roads through wetlands…. if we leave them wetlands at all.
Roads, wetland loss, introduced predators, even pet cats and dogs, it’s a dangerous world for our booming bittern.
So, what can we do for old stabby beak?
- Be a responsible pet owner – at home and out-and-about. Check out this blog for some tips.
- Trap introduced predators like stoats and rats, even a backyard trap helps!
- Drive slowly around wetlands and flooded drains – why not take the opportunity to spot a bittern, rather than potentially hit one?
MIL OSI
