A blog post by Tom
The genus Mohoua is a small group of three birds species endemic to New Zealand: the pīpipi/brown creeper (Mohoua novaeseelandiae), the pōpokotea/whitehead (Mohoua albicilla) and, the subject of this post, the mōhua/yellowhead (Mohoua ochrocephala).
Emma and I have had encounters with pīpipi and pōpokotea before but, until visiting Whenua Hou, the mōhua had eluded us. All three species look similar in their shape, rough size and general mannerisms, but the mōhua is arguably the most striking.
We heard the mōhua before we saw them. Like our experiences with their cousins, they were most often spotted high above us in the trees peering down and chattering to one another.
A Few Mōhua Facts
Where are they found?
The mōhua is a forest dwelling song bird found only in the southern half of New Zealand.
What other names are they known as?
They are known by many names including yellowheads, bush canaries or custard heads (as their conservation scientists affectionately call them).
What do they eat?
They are mainly insectivorous. They spend a lot of time gleaning insects from the moss and bark of trees.
What do they look like?
They are small in size, being only about 15cm in length. As you’ll have seen in our photos, they have conspicuous yellow heads and breasts. They have rigid tail feathers which act as a prop for the birds as the work their way around a tree searching for insects. Their tail feathers are often very worn as a result of this.
What do they sound like?
Their call is often described as machine-gun like, a rapid chatter amongst cheerful melodic notes. Listen here and on the New Zealand Birds Online website. As they often forage in groups, they can create quite a cacophony!
Where do they lay their eggs?
They nest in tree hollows and can produce up to 4 eggs in a clutch.
The Usual Story
This will be a familiar story to all New Zealand naturalists: The story of the mōhua’s decline to near extinction.
Not so long ago, back in the 1800s, mōhua were very common. Being brightly coloured, they would have been a regular splash of yellow amongst the almost entirely green-brown native bush. Early European settlers named them bush canaries because they flocked together making incessant, melodious calls. However, this was not to last. With the arrival of these European settlers came deforestation and the introduction of predators in the form of rats, cats, stoats and possums to name a few. Soon, mōhua were driven from most native forest types except a few beech forests which provided enough insect food for them to hold on.
What are we left with?
According to the Department of Conservation, the mōhua’s population is currently less than 5000 birds. They are now absent from 75% of their historic range.
The 30 populations that are left can be split into four broad groups: populations east of the Southern Alps, Fiordland birds, Southland/Otago hill country birds, and those on predator-free off-shore islands (including those on Whenua Hou). Some of the islands where mōhua are now found were populated by purposefully translocated birds in order to help safeguard the mōhua’s future.
The Department of Conservation initiated the Yellowhead/mōhua recovery plan which has the goal to “maintain and enhance mōhua populations throughout their present range and beyond, by halting and reversing the degradation of the forest ecosystem.” There is also the Mōhua Charitable Trust which is dedicated to restore Mōhua and other native fauna populations back to the numbers that were once found in New Zealand’s native forests.
A Positive Note
Unlike many of the declining New Zealand native birds, mōhua have a life history trait which can act in their favour when it comes to their chances of population recovery: They can lay 4 eggs in a clutch and can produce two clutches in a good year. This means that with the right kind of conservation measures (measures which allow them the chance to breed, find nest spots, a good amount of food and avoid predation) could result in strong population gains.
An example of this in action can be found in the Landsborough Valley in South Westland. Following sustained predator control to suppress rats, stoats and possums, the mōhua’s population increased 30 fold to become the most common bird counted in the study area in 2019. You can read a news story about it here.
Here is hoping that with a little help, those living down south will not have to travel far to hear and see these birds in the future as they slowly return to their historic range.
Until Next Time
(…”next time” has been taking quite a while these days!)
Now we have met the mōhua, it will soon be time to spot some sundews (the focus of Emma’s next post). Read more about Whenua Hou and our other wildlife encounters here:
References and Further Reading
Department of Conservation – Yellowhead/Mohua – https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/yellowhead-mohua/
The Mōhua Charitable Trust – Homepage – http://www.mohua.co.nz/index.html
New Zealand Birds Online – Yellowhead – http://www.nzbirdsonline.org.nz/species/yellowhead
Scoop – Mohua goes from rare to common in 21 years – https://www.scoop.co.nz/stories/SC1905/S00011/mohua-goes-from-rare-to-common-in-21-years.htm