Huia (Heteralocha acutirostris)
|Size||Length: 48 cm (2)|
Classified as Extinct (EX) on the IUCN Red List (1).
Now extinct, the huia was remarkable for the extreme difference in the shape and size of the bill between the sexes, initially causing them to be described as separate species (1) (2). The female’s bill was slender, markedly downcurved and averaged 96 millimetres in length; in contrast, the male’s bill averaged 60 millimetres, and was broad and only slightly downcurved (3). Both sexes had entirely black plumage with a green, metallic sheen; long tail feathers ending in a broad, white (or reddish-white) band; and two bright orange, fleshy wattles at the base of the bill. The juvenile was a duller brownish-black, and the band at the tip of its tail was reddish-white, becoming whiter with age. The huia’s call was a soft, flute-like whistle (2).
Before the arrival of humans, this New Zealand endemic was widely distributed. However, the arrival of the Maoris, and later the European settlers, caused the huia’s range to contract to the southern portion of North Island (4) (5). The last official sighting of the bird was made in 1907 in the Tararua mountain range (5)
The huia was found in primary forest covering the extensive mountain valleys of North Island (2) (4).
A monogamous species, the huia was believed to form lifelong breeding pairs, which lived in close association. Breeding occurred in early summer, with the female laying a clutch of two to four eggs in a saucer-like nest constructed from dried grass, leaves and twigs (5).
While both sexes fed extensively on the grubs of the large nocturnal beetle (Prionoplus reticularis), which inhabit decaying wood (2), the differences in bill shape and size allowed the male and female to obtain the grubs from different sources, potentially reducing competition for food between the sexes (6). The male used its stout beak to chisel into the surface of the wood exposing its prey, while the female used its long, slender beak to probe into cavities and burrows in the wood that were inaccessible to the male (2). Due to misinterpretations of a late 19th century account of the huia, there has been some confusion about whether breeding pairs assisted each other in foraging. Although the male’s feeding behaviour certainly exposed previously inaccessible grubs to the female, it is unlikely that this was a deliberate cooperative strategy (3). The huia also fed on berries and other invertebrates, generally preferring to hop, rather than fly, between tree branches and along the forest floor as it foraged (2) (5).
Although the exact cause of the huia’s extinction is not entirely clear, overhunting, habitat loss, and disease have all been implicated (4). In Maori culture, the huia was extensively hunted for its highly-valued feathers. While this may well have caused a decline in the huia’s population, it was the arrival of European settlers that sealed this species’ fate. An international fashion for wearing huia feathers, as well as a demand for huia specimens as biological curiosities, led to a dramatic increase in hunting pressure. In addition, the arrival of the Europeans also caused the loss of many grub-infested, dead trees through deforestation, reducing the huia’s food supply and habitat. As a final factor, the Europeans introduced non-native animals, which may have been carrying diseases to which the huia had no natural resistance (5).
As it became clear that the huia’s population was in severe decline, laws were passed to ban its hunting; unfortunately, these were largely ignored, and overexploitation of the huia continued until its eventual extinction (5).
Today, Forest and Bird, a New Zealand conservation organisation, is working to ensure that New Zealand’s native species and habitats are preserved, so that tragic extinctions like that of the huia no longer occur (7).
To find out more about Forest and Bird’s conservation work visit:
- Forest and Bird:
For more information on this and other bird species please see:
- BirdLife International:
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- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Invertebrates: animals with no backbone.
- Monogamous: having only one mate during a breeding season, or throughout the breeding life of a pair.
- Nocturnal: active at night.
- Primary forest: forest that has remained undisturbed for a long time and has reached a mature condition.
- Wattles: fleshy organs that hangs from the bill, throat or eye of some bird species.
IUCN Red List (June, 2013)