The kererū (Hemiphaga novaeseelandiae) or New Zealand pigeon is the only pigeon endemic to the New Zealand mainland. A large conspicuous pigeon with distinctive noisy wingbeats, it is the only remaining New Zealand bird capable of swallowing large fruit, and so is an important seed disperser for native trees. Kererū were a significant food source for Māori and one of the two foods harvested at the New Year. Although widespread in both forest and urban habitats, their numbers have declined significantly since European colonisation and the arrival of rats and possums, and hunting them is now illegal.
Kererū" (singular and plural) is the most common Māori name, and now the most common name used in New Zealand English. It is also known as kūkupa and kūkū in some parts of the North Island, particularly in Northland. The name is increasingly spelled with the macron that indicates a long vowel. Kererū are also called wood pigeon, but are distinct from the wood pigeon (Columba palumbus) of the Northern Hemisphere, which is a member of a different genus.
The kererū is a large, 550–850 grams (19–30 oz), arboreal fruit-pigeon found in forests from Northland to Stewart Island/Rakiura and offshore islands; kererū bone has been recovered from Raoul Island in the Kermadecs. It can be found in habitats from coastal to montane. Its morphology is that of a typical pigeon, in that it has a relatively small head, a straight soft-based bill and loosely attached feathers. It also displays typical pigeon behaviour, which includes drinking by suction, a wing-threat display, hitting with the wing when threatened, a diving display flight, a 'bowing' display, ritualised preening and 'billing' during courtship. New Zealand pigeons build flimsy, shallow, twiggy nests and feed crop milk to hatchlings.
The mainland New Zealand pigeon grows to some 51 centimetres (20 in) in length and 650 grams (23 oz) in weight, compared to 55 centimetres (22 in) and 800 grams (28 oz) for the Chatham Island variant. The head, throat and wings are generally a shiny green-purple colour, but with a bronze tinge to the feathers. The breast is typically white and the bill red with an orange-ish tip. The feet and eyes are red. Juveniles have a similar colouration but are generally paler with dull colours for the beak, eyes and feet and a shorter tail.
Kererū make occasional soft coo sounds (hence the onomatopoeic names), and their wings make a very distinctive "whooshing" sound as they fly. The bird's flight is also distinctive. Birds will often ascend slowly before making impressively steep parabolic dives; it is thought that this behaviour is often associated with nesting, or nest failure.
There are two subspecies of New Zealand pigeon: H. n. novaseelandiae of mainland New Zealand and the Norfolk pigeon (H. n. spadicea) of Norfolk Island, now extinct. The subspecies differed in their plumage colour and shape.
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In 2001, it was proposed that a third subspecies, H. n. chathamensis or the Chatham Island pigeon, was distinct enough to be raised to full species status as H. chathamensis. This has since been accepted by most authorities. Recovering from a low of 40 birds in the 1980s, the Chatham Island pigeon population is now over 600, and the species is ranked by the IUCN as "Vulnerable", and by the New Zealand Department of Conservation as "Threatened".
The kererū belongs to the family Columbidae, and the subfamily Ptilinopinae, which is found throughout Southeast Asia, Malaya, Australia and New Zealand. The members of this subfamily feed largely on fruits, mainly drupes. Both New Zealand pigeons are members of the pigeon genus Hemiphaga (Bonaparte, 1854), which is endemic to the New Zealand archipelago and Norfolk Island.
I may have gone too far with this one, but there's so much known about this bird, that I can't fit it all.
One more thing worth noting, is that this pigeon is well known for eating fermented fruit to the point of getting drunk
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In 2001, it was proposed that a third subspecies, H. n. chathamensis or the Chatham Island pigeon, was distinct enough to be raised to full species status as H. chathamensis. This has since been accepted by most authorities. Recovering from a low of 40 birds in the 1980s, the Chatham Island pigeon population is now over 600, and the species is ranked by the IUCN as "Vulnerable", and by the New Zealand Department of Conservation as "Threatened".
One more thing worth noting, is that this pigeon is well known for eating fermented fruit to the point of getting drunk