Kauri comparisons: Kererū

Shanti Truong-George

Kauri Protection Coordinator

The iconic kauri tree is unique among Aotearoa’s native species, but also shares characteristics with some of our other flora and fauna. This is the first in a series of blog posts dedicated to learning more about the mighty kauri, through comparing its differences and similarities to some of our other native species.

E koekoe te tūī, e ketekete te kākā, e kūkū te kererū - The tūī chatters, the kākā cackles and the kererū coos.

The kererū or kukupa is another truly iconic native species. The whakataukī above not only relates to our native manu, but also talks about listening and appreciating all voices and songs to create great music for the future (Kia Kaha te Reo Taiao). Once said to be found in flocks of hundreds, the kererū is a native wood pigeon and is one of the largest in the world. Kererū have a distinctive look, with no other birds on the mainland looking like them.

They have green heads and upper chest, and wings, which shift into a dark purple. Contrastingly, their underparts are bright white. They can also be recognised from the loud flap of their wings as they fly, which is the main way you will hear them. Kererū like to eat fruit, but can also eat the leaves, buds and flowers of plants.

Kererū can be seen throughout Kaipātiki, no doubt helped by the pest control efforts of the different halo groups. If you live in the Kaipātiki region and are interested in installing your own pest control, feel free to come into Puāwai, the Pest Free Kaipātiki office, and have a chat with us.

Same or Different?

Kererū are the same as kauri trees because both species are considered ‘ecosystem engineers’ and ‘keystone species.’ Kauri trees are ecosystem engineers because of their acidic leaf litter. Kauri trees are evergreen, so they do not lose all of their leaves during the winter. Instead, their leaves will die off and regenerate individually. On the ground, the dropped leaves are slightly acidic, which, combined with rain, leeches into the soil. This changes the soil composition and creates a nutrient-poor clay-like soil called kauri podsol. Kauri trees will therefore ‘engineer’ the ecosystem around them, creating an environment that they can thrive in, but other species cannot.

On the reverse of this, some species of plants thrive in the soil generated by kauri trees, so they are known as ‘kauri associates.’ Without the nutrient-poor soil as a filter, these kauri associates could be outcompeted by other plants, meaning that they rely on kauri to survive. One example of a kauri associate is the kauri orchid; read more about it in our ‘kauri friends’ blog post. The reliance of other plants like the kauri orchid on kauri trees also makes them a keystone species, because they disproportionately affect the ecosystem’s community of species (who gets to live in a certain location).

Similarly, the kererū is a key stone species, because some of our native tree species - like taraire, tawa and karaka - rely on kererū to disperse their seeds. In the past, New Zealand had a range of large bird species; however, kererū are now the only birds left with big enough beaks to eat and disperse large seeds. This makes kererū ecosystem engineers and keystone species, because, like kauri trees, they also shape the community of species around them.

Without kererū, we could also lose our native tree species. Kererū do the job of restoration naturally, so they are key in the effort of regenerating our native forests. To help protect the kererū of Kaipātiki, you can plant native trees, do pest control on your property and put up window stickers to prevent bird strikes.

Look out for the next post in this series: the moho pererū (banded rail)