The kererū or New Zealand pigeon (Hemiphaga novaeseelandiae) is a plump purple and bottle-green pigeon with a white bib, and red eyes, bill and legs. Kererū are about 50 centimetres long and 650 grams in weight.
Kererū eat the fruit of native plants such as miro, tawa, pūriri, taraire, kahikatea, nīkau and coprosma, and introduced plants like privet, elderberry and plums. When fruit is scarce they eat leaves, favouring kōwhai, tree lucerne, willow and poplar.
Since the extinction of large birds such as the moa, the kererū plays a vital role in the regeneration of forests. A member of the fruit-pigeon subfamily, it is now the only fruit-eater large enough to swallow fruit with large seeds, ensuring that future generations of trees such as tawa, miro, karaka and nīkau are widely spread.
Māori and kererū
To Māori, the plump kererū was an important source of food, being plentiful and tasty eating. In Northland and parts of Canterbury the bird is known as kūkupa.
In one tradition, it gained its striking plumage when the demigod Māui, trying to find out where his mother went each day, hid her skirt to delay her. When she went to the underworld without it, Māui changed into a white pigeon and followed her. He was still holding the skirt, which became the kererū’s white breast and purple-green neck feathers.
Kererū occur throughout mainland New Zealand, and on Stewart Island and many offshore islands. They are most common in the lowland forests of Northland, the King Country, Nelson and the West Coast, but are in danger of becoming locally extinct in Northland because of poaching and predation.
Kererū perform spectacular mating displays, flying high into the air from a perch, then diving steeply before pulling out of the headlong fall. Their nest is an untidy platform of sticks in the fork of a tree or among vines. Laying begins in September (spring) and can continue through to February, depending on fruit availability. Kererū lay a single white egg, which both adults incubate for a month. They can breed again after fledging a chick, and sometimes raise three chicks in a season.
Long way for a meal
Kererū fly considerable distances in search of food, including across 30-kilometre Foveaux Strait, between Stewart Island and Invercargill. By contrast, their Chatham Islands relative, the parea, rarely flies further than 5 kilometres.
At first, the rapidly growing chick is fed a rich milky secretion from both parents’ crops (pouches in their upper digestive tracts). It is later fed on regurgitated fruit for four to six weeks. After the chick fledges, the parents continue feeding it by regurgitation for several weeks. When food is abundant, adults may renest, even while still feeding the fledgling. Kererū can live at least 21 years.
Kererū at risk
Protected from hunting since 1912, kererū remain at risk for four major reasons:
- They have a low breeding rate, breeding only when forest fruit is abundant.
- Possums and rats compete for the same food.
- They are an easy target – cats kill adult birds feeding on low plants, and rats and stoats take eggs and chicks from the nest.
- They are hunted by people for food, despite being protected.
The parea or Chatham Island pigeon (Hemiphaga chathamensis) is closely related to the kererū. But it is paler on the back, and a fifth larger, weighing 800 grams – making it one of the world’s largest pigeons. The parea population dropped to less than 50 in the 1980s, due to forest clearance and introduced predators, but it has rebounded to over 600 thanks to work by the Department of Conservation and the local community.