The kererū (Hemiphaga novaeseelandiae), also called kūkū, kūkupa, wood pigeon or simply New Zealand pigeon, is endemic and one of Aotearoa New Zealand’s most valuable assets when it comes to native bush regeneration. It is one of our most iconic birds with its beautiful blue-green and white plumage. A bird that you often hear before you see, the noisy beat of its wings makes a distinctive sound as it flies from tree to tree.
The kererū is a large bird, measuring up to 510 mm from tail to beak and weighing on average 630 g, and is found throughout New Zealand.
Kererū are protected birds and endemic to New Zealand. Conservation efforts to restore the kererū’s habitat and increased pest control has helped to slow the decline in kererū numbers.
Essential for seed dispersal
The kererū has the widest gape of all New Zealand native birds, which allows it to eat large berries. This makes them vital to our forest ecosystem, as trees such as karaka, miro, tawa and taraire rely on them for seed dispersal. Kererū are one of New Zealand’s keystone species, essential for the ongoing propagation of some of our native plant species.
Some seeds need to pass through the gut of a bird to properly germinate. With the extinction of the moa, kererū are the only seed dispersers with a bill big enough to swallow large fruit.
They have been called our “gardeners of the sky” due to their unique ability to disperse these large seeds.
Though the orange karaka berries are a major food source for kererū, the fresh kernels contain the alkaloid karakin, which is highly toxic to other animals. Dog owners have been warned to keep a close eye on their dogs to ensure they do not eat the berries, as this can be fatal. Our native species have evolved so that they can safely eat plants that others would find poisonous, for example, native bees are not harmed when they collect honeydew from tutu.
When fruit and flowers are not available, kererū will eat the leaves of trees such as kōwhai, tree lucerne, broom, willow, elm and poplar.
Occasionally, kererū gorge so heavily on ripe fruit that they become very full or drunk – as the fruit ferments inside them in the hot sun, they have been known to fall out of trees.
Kererū are monogamous and are often seen in pairs. In good conditions, they can live up to 21 years, but they are slow breeders with only one egg laid per clutch. In a good breeding season when there is lots of fruit available, they could raise three chicks, but in years where there is little to no fruit available, no eggs are laid. Eggs are usually laid between September and April with both parents sharing incubation.
Kererū are unusual in that they are one of only a few birds that produce crop milk to feed their chicks, it is a protein-rich milky secretion from the walls of the parents’ crops. When the chicks are a bit older this is combined with fruit pulp until it leaves the nest at about 40 days old.
How you can help
Kererū are not fussy eaters – they browse on over a hundred native and 50 exotic, shrubs and trees. To help increase kererū numbers, plant kererū-friendly native plants in your garden such as rimu, ngaio, kōwhai, karaka, mataī, harakeke and rewarewa – a full list is on the Kererū Discovery website.
From the data we already have, we know that some of the best ways people can help kererū in their community is by planting trees like kowhai which is the most common tree people have seen kererū feeding on.Dr Stephen Hartley, Director of the Centre for Biodiversity & Restoration Ecology, Victoria University of Wellington
Don’t forget to also lay pest traps to help protect the kererū, and if you are in an area with kererū around, consider putting decals on your windows to help prevent kererū flying into the glass. The Hub has a range of resources around predator-free New Zealand including a practical student activity for monitoring pests – Making a tracking tunnel.
In October 2017, the New Zealand Transport Agency approved a new road sign asking drivers to slow for kererū in some urban areas and in areas with roads passing through native bush corridors. Kererū can often take a while to get elevation when they take off, which puts them at risk of being hit by cars, especially when they are feeding on vegetation that is close to the ground.
The Great Kererū Count citizen science project
For 10 days in September during 2014 to 2021, New Zealanders were asked to count kererū as part of one of New Zealand’s biggest citizen science projects. The aim was to gather information from across New Zealand on the abundance and distribution of kererū. During the eight years this project ran, citizen scientists contributed to a total of 64,036 observations and 144,472 kererū were counted. This helped create a statistically significant database to understand and secure the future of these birds.
Kererū numbers are much lower than the flocks reported from 50–100 years ago, but as kererū do not have formal threatened status classification, the Great Kererū Count was the only centralised data gathered to monitor the overall national trends.
Sam Rammell (student at the Centre for Biodiversity and Restoration Ecology, Te Herenga Waka – Victoria University of Wellington) created these interactive maps to tell the story of the last Great Kererū Count data collection in 2021. Not only do the maps provide data on the number of kererū from around New Zealand, but also data on urban versus rural sightings, flock size, forest type and food preference. Sam is running an analysis on the eight years of data.
New Zealand has one other species of native pigeon – the parea or Chatham Islands pigeon (Hemiphaga chathamensis), which is classified as nationally vulnerable. The parea is about 20% larger than the kererū, making it one of the heaviest pigeons in the world, with a bigger bill and greyer feathers. It is mainly restricted to southern Chatham Island, and it’s main habitat is the forest.
Parea are another great conservation success story. In 1989, it was estimated that there were only 45 birds left. Pest control, particularly of feral cats, has led to an improvement in the species’ improved conservation status, and a 2009 survey estimated that there were over 600 birds. This led to the conservation status being moved from nationally critical to nationally vulnerable in 2013.
Read more about our birds’ roles in ecosystems, then follow up with the activity New Zealand bush ecosystems where students build a food web and explore the relationships between organisms.
Conserving native birds – introduction curates Hub resources about native bird conservation, their roles in ecosystems, adaptations and more.
See Kererū Discovery and data from The Great Kererū Count for more kererū information.
Read this Stuff news article: More kererū than ever recorded as final national count wraps up.
Samuel Rammell, Te Herenga Waka – Victoria University of Wellington created a story with interactive maps about the 2021 survey findings.
For more detailed information on kererū, visit New Zealand Birds Online.
Te Kura Huna o Te Urewera is a 2-part documentary covering the research of Manaaki Whenua-Landcare Research researchers and the Tūhoe Tuawhenua Trust who worked closely over several years with the Ruatāhuna community to explore Tuawhenua’s relationship with the kererū and Te Urewera.
Watch these videos from the 2016 LEARNZ Kererū Count virtual field trip.