Huia

When males and females look like two different species

The particularly pronounced sexual dimorphism between female and male huia caused confusion in the past. It even went so far that the English ornithologist John Gould in 1836 described male and female huia as different species. Even today, scientists debate how this sex-specific bill shape and length came about, as nothing comparable is known in any other bird species. The larger females had a long, slender, downward-curving bill, while the smaller males had a short, powerful bill similar to a crow’s.

Although the huia is often mentioned in specialist literature because of the pronounced differences between the sexes, little is known about its lifestyle and behaviour. Before it went extinct, there was hardly any time to study the species in depth. Much of what we know today about the huia comes from the notes of the New Zealand ornithologist Walter Buller, who spent the second half of the 19th century studying the huia in detail.

Like the probably extinct South Island kōkako, the huia belongs to the wattlebird family (Callaeidae), which occurs exclusively on the islands of New Zealand. The huia typically had black plumage with a greenish sheen, and its throat wattles on either side of the base of the ivory-coloured bill were bright orange and hard to miss. Adult huia had twelve long black tail feathers with a broad white tip.

Huia – fact sheet

scientific names	Heteralocha acutirostris, Neomorpha acutirostris (female), Neomorpha crassirostris (male), Neomorpha gouldi, Heteralocha gouldi
original range	North Island of New Zealand
time of extinction	1907 at the earliest
causes of extinction	habitat loss, hunting, animals introduced to the island and diseases
IUCN status	extinct

The huia preferred primary mixed forests

Subfossil finds and bone deposits indicate that the huia once lived both in the lowlands and in the montane forests of the North Island. Reports collected by Buller and a Māori song called “waiata” suggest that the huia once also occurred in the Marlborough and Nelson districts of the South Island. However, this has not yet been proven by fossil finds.

With the beginning of the settlement of the North Island by the Māori in the 14th century, the huia disappeared from the northern and western parts of the island. And when Europeans arrived on the North Island in the 1840s, the bird’s range was limited to the Ruahine, Tararua, Rimutaka and Kaimanawa mountain ranges in the south-eastern part of the North Island.

The huia inhabited both of New Zealand’s original primary forest types: temperate rainforest and the Southern Beech Forest with southern beeches (Nothofagus). It preferred Nothofagus-Podocarpus–mixed forests.

Different bill shapes as a feeding strategy?

Like the extinct North American ivory-billed woodpeckers and Cuban ivory-billed woodpeckers, huia fed on insect larvae living in dead wood as well as berries and seeds. Since there are no woodpeckers in New Zealand, their role was filled by the huia (now extinct) and the threatened forest parrot, the kākā (Nestor meridionalis).

In rotting wood, the huia searched for insect larvae. Scientists assume that the huia specialised in the larvae of the nocturnal huhu beetle (Prionoplus reticularis), considered the heaviest beetle in New Zealand, but it also ate other insects such as grasshoppers or spiders.

Buller and many other scientists initially assumed that the different huia bill shapes might be related to the birds’ feeding strategies: the male chiselled insects and larvae out of the bark of rotten and decaying wood with its short bill, like a woodpecker. In doing so, it removed the outer layers of dead wood. The female then used her long, slender bill to probe larval tunnels in the wood that were out of reach for the male—and which the male could not break open because the wood was too hard.

Buller’s theory is based on observations of a huia pair kept in captivity and fed on larvae. Today, however, scientists assume that the different bills are an extreme example of niche differentiation that reduced intraspecific competition between the sexes. This view is held, for example, by the biologist Ron J. Moorhouse in The extraordinary Bill Dimorphism of the Huia: Sexual Selection or intersexual Competition? (1996). According to this, the different bill shapes would have enabled the species to use a wide range of food sources in different microhabitats.

In 1974, ornithologist Philip J. K. Burton studied the anatomy of the huia’s neck and head and found that males and females differ not only in bill shape, but also that the structure and musculature of the neck and head show differences. Burton also found that huia had very strong jaw muscles, allowing them to open their jaws with considerable force.

Were there also white huia?

The Māori, the Indigenous people of New Zealand, referred to some huia as “huia-ariki”. These birds had brownish plumage with greyish tones; the head and neck were darker. Scientists disagree on whether these were partial albinos or simply very old birds.

There are also reports of huia that were said to have been completely white. Dutch illustrator John G. Keulemans painted one of these white birds around 1900. In 2013, ornithologist Julian P. Hume and Hein van Grouw, curator of the ornithological collection at the Natural History Museum in London, examined the white bird in Colour Aberrations in extinct and endangered Birds.

Since the white huia painted by Keulemans appears to be fully grown, the two scientists rule out albinism. They consider it more likely that progressive greying, leucism or an ino mutation caused the pale plumage. It is also questionable how such an atypical huia could have survived to adulthood. It would certainly have been highly sought-after by collectors.

Leucism—a congenital mutation in which the skin lacks pigment cells, resulting in white fur and pink skin—is very rare in wild birds. This theory can therefore also be ruled out as a cause for the huia. Ino mutations, known for example from budgerigars, are not unusual in wild birds, which is why Hume and Grouw favour this explanation. After all, fresh plumage in inos can be very pale, almost pure white. Although ino birds have reddish eyes due to the lack of melanin, they do not suffer from poor eyesight like albinos. This means ino birds can cope in the wild.

The scientists were unable to locate a pale huia in ornithological collections, which is why they cannot explain the colour deviation with absolute certainty. However, the fact that the bird painted by Keulemans is a female underscores that it was an ino. The reason: the ino mutation is a sex chromosome-linked, recessive mutation on the Z chromosome, a sex chromosome in birds. This means that as soon as females carry a mutated ino gene, the mutation is visible, because female birds have only one Z chromosome. Male birds have two Z chromosomes, and if only one of them carries a mutated ino gene, it will not be visible—but the male can pass the mutation on to its offspring.

The Māori and the huia

The Māori did not hunt the rare huia to eat them, but for their feathers, which were used to adorn people of high rank. The birds were quite curious, which made them easy for the Māori to catch. The hunters also imitated huia calls to lure the birds in, then caught them with a snare or killed them with a club or spear.

The Māori also exploited a particular trait of huia for hunting: the birds were monogamous and spent their entire lives with the same partner. If the Māori caught one bird, its calls would inevitably attract its partner, which could then also be captured with little effort.

The huia’s range was not very large, but its tail feathers were found in the far north and the extreme south of New Zealand. Māori tribes traded huia feathers for other valuable goods such as shark teeth. The feathers were used, for example, to decorate the heads of the deceased, as adornment at funerals, or to decorate chiefs’ dwellings.

Māori created various ornaments from huia. The marereko, for example, was a feather headdress consisting of twelve feathers. The pōhoi, a neck or ear ornament, consisted of dried huia skin—the bird was skinned except for the bill, wattles and skull, and the legs and wings were removed. Māori also wore dried huia heads as pendants, known as ngutu huia. It was also not uncommon to keep huia in cages and, once they had grown to full size, pluck out their tail feathers.

The significance of the feathers is also reflected today: in April 2024, a single huia feather was auctioned in Auckland for a record price of around €26,000, underscoring its enduring appreciation and rarity. And for an auction taking place in London in October 2024, estimates suggest that up to €71,000 could be achieved for a stuffed huia pair.

Deforestation deprived the huia of its livelihood

Huia were already rare when Europeans began to settle New Zealand. But with the massive deforestation on the North Island to create agricultural land for the new settlers, the birds quickly became even rarer. The species reacted particularly sensitively to this change, because it could only live in old forests—forests with plenty of rotten trees where it could find wood-boring insect larvae. In secondary forests regenerating after slash-and-burn or logging, huia found no food and could not survive.

Even though logging mainly affected the lowlands and the mountain regions were largely spared, there was an enormous population decline in huia. Scientists suspect that the huia needed the lowland regions as a winter refuge in order not to be exposed to snow and extreme cold in the mountains.

Invasive species, exotic diseases and greedy naturalists

Of course, mammals also reached New Zealand with Europeans. In Die ausgestorbenen Vögel der Welt (1986), Dieter Luther points to the “faunal distortion” that accompanied European settlement as a cause of extinction. This was caused by the introduction of around 35 mammal species, including dogs, mustelids, rats, cats, rabbits and red deer. The almost flightless huia, which spent its time hopping on the ground or in the lower and middle tree layers, was certainly easy prey for these invasive species.

In this context, the IUCN puts forward the hypothesis that the introduction of the originally Asian songbird common myna (Acridotheres tristis) and its parasites and diseases accelerated the huia’s extinction. This assumption is based on the fact that scientists were able to detect African and Asian ticks on museum skins. According to entomologist John G. Meyers in The present Position of endemic Birds in New Zealand (1923), these were probably introduced along with common mynas.

The common myna, which also preys on the eggs and chicks of other birds, is considered a threat to ecosystems and endemic animals. The IUCN therefore counts the common myna—now also found in Australia, Africa and North America—among the 100 of the World’s Worst Invasive Alien Species.

All bird species endemic to New Zealand faced habitat loss and introduced mammals, but huia were also heavily hunted. Stuffed specimens were sought-after by wealthy collectors in Europe and by museums around the world. In essence, the hunt for the birds was driven by naturalists. For example, Austrian taxidermist Andreas Reischek brought 212 huia pairs to the Natural History Museum in Vienna over a period of ten years. This is stated by Michael Szabo in the New Zealand Geographic article Huia, The Sacred Bird (1993).

But the Māori also contributed to the species’ decline through lively trade in the bird. In A History of the Birds of New Zealand (1888), Buller reported that in 1883 a group of eleven Māori received 646 huia skins in a barter trade. As part of this, several thousand birds were reportedly exported overseas.

Attempts to save the huia—and how they failed

New Zealand’s government made a few attempts to prevent the huia from going extinct, but they were few in number, not legally secured and poorly organised. The New Zealand conservation movement was still in its infancy in the 19th century.

In early 1892, the Wild Bird Protection Act was even amended to prohibit killing huia. The problem was that no one complied. Moreover, huia were never relocated to island sanctuaries for endangered native birds. In this context, an anecdote from Kerry-Jayne Wilson’s Flight of the Huia (2004): in 1893, a pair was supposed to be taken to Kapiti Island for protection, but Buller prevented this and took the pair—as well as the last collected living pair of laughing owls (Ninox albifacies)—to England as a gift for Lord Rothschild. From 1901 onward, the huia was no longer considered a protected species in New Zealand during the hunting season.

The last sightings—and how cloning also failed

The last confirmed huia sighting was in December 1907, when W. W. Smith saw three birds in the forests of the Tararua Range in the south of the North Island. Unconfirmed but “quite credible” sightings suggest that the huia went extinct later. For example, a man familiar with huia reported seeing three birds in Gollans Valley behind York Bay in December 1922. Sightings from 1912 and 1913 are also documented for the same region. The last credible but unconfirmed sightings came from the forests of Te Urewera National Park: in 1952 near Mount Urutawa, as well as in 1961 and 1963 at Lake Waikareiti.

Some scientists believe that a small surviving huia population still exists in the Urewera Range, but most consider this unlikely. In recent times, there have also been no expeditions with the aim of finding a living bird.

In July 1999, scientists and ethicists met and decided that the huia should be cloned; CNN reported on it. However, the condition of the DNA in the museum skins turned out to be too poor, so that no complete huia genome could be obtained for cloning.

With the huia, the bird louse Rallicola extinctus also went extinct

When researchers found feather lice infestations on several museum specimens and took a closer look, they discovered a previously unknown—and already extinct—insect species: an animal louse from the family Philopteridae, which includes ischnoceran and chewing lice (Mallophaga) that usually live parasitically on birds. The louse found on the huia, Rallicola extinctus , probably lived exclusively on this bird species and was specialised on the huia as its host.

The disappearance of many bird species is associated with the loss of host-specific insect forms. Many parasite species were only discovered in skins after a bird species had already gone extinct. A famous example is the passenger pigeon mite, whose host, the passenger pigeon, went extinct in 1914. But it doesn’t always have to be a bird: with the Caribbean monk seal, the nasal mite Halarachne americana also disappeared in the mid-20th century.