The Waiata of Wellington
By Freya Bacon-Bootham
Vibrant, unique manu/bird song greets me every time I step out my front door and is a hallmark of home. Whenever I am out of Whanganui-a-Tara/Wellington, it is one of the things I miss the most.
Tūī are the most prominent and often the loudest manu singing outside my home. The coo of the kererū and cheet-cheet of pīwakawaka are also frequently heard and recently the scrark from kākā flying overhead back towards Zealandia Te Māra a Tāne has joined the composition.
Kākā in flight - photo by Tong Hou | Tūī - Photo by TM Davidson
Accompanying them are the pīwakawaka, who vary their songs across the country, with the North Island species hearing shorter elements at a faster rate and frequency. Their cheet-cheet song is heard year-round except for cold, rainy days when they are quiet. The loud tūī have the most complicated song of Aotearoa New Zealand’s manu, creating a wide array of noises, including mimicking car alarms and complicated trills.
A particularly special moment which showcases Aotearoa’s manu singing is the dawn chorus. Tūī start first, with many scientists believing this is because tūī sing across such a range of frequencies; singing alone gives them the best chance of being heard. The toutouwai/North Island robin follows the tūī, with pīwakawaka joining in later. The beginning of the dawn chorus was so predictable that Māori used it as both an estimation of how long till dawn and as an affirmation of life.
Pīwakawaka/fantail - photo by Scott Langdale | Toutouwai/North Island Robin - Photo by TM Davidson
Unlike humans, who use our larynx to produce noise, manu use a syrinx. A syrinx is a box-shaped organ that lies at the bottom of the windpipe. The air from their lungs passes through the larynx and windpipe, which work together to alter the characteristics of the sound. A longer windpipe will produce a deeper sound, and some manu use muscles to change the length of their windpipe, allowing them to alternate the frequency of their call partway through. Tūī are special manu and have two syrinxes which they use to produce their complex songs and calls.
Aside from complex songs, tūī also use wing noise as part of their communication with each other. This aggressive wing noise is controlled by the manu, as there are gaps in the sound, and it ends abruptly. These noises are created by indents and bumps in some of the primary feathers creating slots for air to move through. Using the wing slots, tūī create a wide frequency of sound, with the major components mostly occurring at a lower frequency.
Part of the reason the Whanganui-a-Tara manu song is so unique is because of the development of regional accents and dialects. Tīeke/North Island saddleback are an excellent example of manu who sound different depending on where they are in the country. Most manu will develop an accent based on the region they live in, but each population of tīeke also form their own dialects with distinct new phrases. These dialects and accents are important to consider during conservation projects, particularly if translocation is involved. Moving new species into an existing population would have a limited benefit if they could not communicate with each other due to dialect problems.
Tīeke/Saddleback- photo by Scott Langdale | Kākāriki - Photo by Janice McKenna
The comfort I find in the soundtrack created by manu is not one I just imagine. Research has found that not only does manu song improve our mental well-being, but when there’s increased biodiversity, this positive impact is even greater.
However, manu song is changing due to human impacts such as light and noise pollution. Light is an important cue for manu; they use it to know when to start dawn and dusk choruses. With light pollution, manu are singing earlier and struggling to fall asleep. This presents problems because, after a bad night’s sleep, a manu is groggy, just like us, meaning they’re likelier to nap during the day and will sing less. Lack of sleep also makes it more difficult for juveniles to learn songs. The issue with noise pollution is that humans have increased the amount of ambient low-frequency noise. This means that manu must be louder and sing at a higher frequency to be heard. Research has found that tūī close to the motorway are twice as loud as manu in other urban environments and have less complex songs.
Zealandia Te Māra a Tāne uses manu song to measure biodiversity in an area by doing 5-minute bird counts. Rangers walk along a specific route, stop at each marker along the track for 5 minutes, and count every manu they hear and see. While it doesn’t give us specific numbers of many in the sanctuary, they are an easy and valuable way for rangers to track what species are in the sanctuary and what isn’t.
Give the 5-minute manu count a try yourself; if you’re unsure which manu makes which call, head to Birdsong Gully first before trying it out.
5-minute bird count - Photo by Rory Wilsher