Conserving our native kiwi

The kiwi is New Zealand’s most iconic bird – we even call ourselves Kiwis – yet all kiwi species are threatened and require ongoing action to ensure we do not lose these precious taonga.

Most of us know that our endemic kiwi have evolved to be nocturnal and flightless. Many know that, out of all birds, a female kiwi lays the largest egg in proportion to its size, up to 20% of the female’s weight. Some know that (technically) kiwi have the shortest beak of any bird – a bird’s beak is generally measured from the tip to the nostril, and kiwi nostrils are at the end of their long beak. These facts and more make them a very unique species, not just to New Zealanders but around the world.

The kiwi is one of the strangest of birds. It sleeps underground and usually only comes out at night but most remarkable of all, it lays the biggest egg of any bird and when she lays it, it's equivalent in terms of weight to human mother giving birth to a four-year-old child!

Sir David Attenborough

Food

Kiwi use their beak to hunt out their food – mostly small invertebrates, especially earthworms and the larvae of beetles, cicadas and moths. They also eat centipedes, spiders, crickets and wētā. Sometimes fallen fruit and leaves are also eaten. The whiskers at the end of their beak help them with nocturnal navigation, and they have an excellent sense of smell.

Plumage

As they do not fly, kiwi feathers are different to other birds as they have adapted to suit a ground-based life. The feathers are warm, shaggy and hair-like, hang loose and are much fluffier. Their plumage provides them with good camouflage, allowing them to blend with the undergrowth in the forest. This protects them from predators finding them by sight – but unfortunately is no good against any predator with a good sense of smell. The various species of kiwi have different colouration and patterns to suit their own environment.

Different species

It was only in the early 1990s that additional species of kiwi were recognised – instead of three we had five. Genetic research by Professor Allan Baker found that the brown kiwi is actually three different species – the North Island brown, the Ōkārito brown or rowi and the southern brown or tokoeka. They are all physically similar, but they are genetically different. Ongoing research into the DNA of kiwi suggests that there could be even more kiwi species – maybe 11.

Common name	Habitat	New Zealand Threat Classification System	Some facts
Great spotted kiwi or roroa Apteryx haastii	Northern half of the South Island	Threatened – nationally vulnerable	The largest and most common of the kiwi species – the population is estimated to be over 15,000. They are less vulnerable to predation due to their extreme habitat – the higher altitudes of South Island national parks. Both parents incubate the one egg laid each season.
Little spotted kiwi Apteryx owenii	Kapiti Island, some other predator-free islands and ZEALANDIA	At risk – recovering	The smallest kiwi. Predation by introduced pigs, stoats and cats has led to this being the only kiwi species to have become extinct on the mainland. Currently there are 1,400 left. The female lays one egg, which is incubated by the male, and the chicks start to fend for themselves from 5–7 days old.
Ōkārito kiwi, rowi or Ōkārito brown kiwi Apteryx rowi	Ōkārito forest area in the South Island and two predator-free islands in the Marlborough Sounds	Threatened – nationally vulnerable	First identified as a new species in 1994. Females lay up to three eggs in a season, each one in a different nest, and both male and female birds incubate the eggs.
North Island brown kiwi Apteryx mantelli	Widespread in the northern two-thirds of the North Island	At risk– declining	Our most common kiwi. In 2008, the Department of Conservation estimated there were about 25,000 remaining, but numbers are steadily declining. They are quite resilient and able to adapt to a wide range of habitats – even non-native forests and some farmland. The plumage is streaky red-brown and spiky. The female usually lays two eggs, which are incubated by the male. Four geographically and genetically distinct forms have been identified: Northland brown kiwi, Coromandel brown kiwi, western brown kiwi and eastern brown kiwi.
Southern brown kiwi, tokoeka or common kiwi Apteryx australis	Various areas in the South Island	See below	The southern brown kiwi is a reasonably common species of kiwi, and three subspecies are recognised, as below. Their feathers were used for ancient Māori cloaks.
Rakiura (Stewart Island) tokoeka Apteryx australis lawryi	Rakiura (Stewart Island)	Threatened – nationally vulnerable	These kiwi are unusual in that they are active during the day. Also uniquely amongst kiwi, they live in family groups, with older chicks sometimes helping with egg incubation.
Northern Fiordland southern brown kiwi Apteryx australis	Fiordland	Threatened – nationally endangered	Sometimes heard along the Milford Track. They usually have just one egg each year.
Haast southern brown kiwi Haast tokoeka	Haast Ranges and a few island sanctuaries	Threatened – nationally critical	This is the rarest subspecies of kiwi with only about 300–400 individuals left. Their reclusive nature and the harsh environment they live in makes them difficult to work with. Currently, 80% of this species are under active management.

Threats to kiwi

Kiwi evolved in an environment free of predators. They built up fat and lost the ability to fly, and they adapted to nest on the ground. Although they have a very good sense of smell and touch, their vision is very poor. When humans arrived and introduced mammals to Aotearoa New Zealand, the kiwi and their eggs were easy prey for rats, stoats, weasels, dogs, cats, possums, wild pigs and more. Early settlers cleared much of the forest areas, decreasing the kiwi’s habitat

To ensure ongoing survival of kiwi, human assistance is required. One of the most successful interventions to date is the development of offshore and mainland sanctuaries. Ecological sanctuaries provide a safe environment with strict predator control, habitat protection and restoration as well as programmes such as Operation Nest Egg.

Conservation efforts at Willowbank Wildlife Reserve

Willowbank Wildlife Reserve in Christchurch is one of the organisations in New Zealand involved in the conservation and management of many of New Zealand’s endangered species, including the kiwi. The Kiwi Breeding Centre staff work in close association with the New Zealand Conservation Trust and the Department of Conservation (DOC) as part of Operation Nest Egg.

DOC staff involved with Operation Nest Egg use transmitters to locate breeding pairs of kiwi in the bush. DOC staff monitor the kiwi closely in order to identify when a female kiwi lays an egg. To ensure maximum egg survival, eggs are removed from the burrows and then carefully transported in heated containers to kiwi breeding and recovery sites such as Willowbank.

Incubation is 70–80 days, and hatching can take up to 3 days. Kiwi chicks do not have an egg tooth like a lot of other birds, so breaking through the tough shell takes a lot of effort. After hatching, a kiwi chick will stay in its burrow for a few days – using its large yolk sac for nutrition. The large external yolk sac can take up to 10 days to be absorbed. Once the kiwi chick reaches 1.2 kilograms, it can withstand attack from predators and can then be released back into the wild.

Willowbank’s captive kiwi breeding programme for North Island brown kiwi

The kiwi breeding programme at Willowbank begins with a number of breeding pairs of kiwi located in a predator-proof outdoor bush area approximately 2 hectares in size. Willowbank has been involved in the breeding and management of four species of kiwi: North Island brown, great spotted, Ōkārito rowi and Haast tokoeka. By mid-2019, this work has led to over 600 kiwi being released back to the wild.

Staff at Willowbank carefully monitor the breeding process through egg collection, candling, incubation and caring for the chick once it has hatched. Kiwi chicks are closely monitored, fed a special diet and weighed regularly to ensure their progress is satisfactory. The kiwi diet mix made up by the staff is measured out according to each individual chick’s weight and needs. After kiwi have been fed overnight, the remaining food is weighed, and this data is collected to identify trends and ensure the kiwi are developing accordingly.

Once a kiwi chick reaches a suitable weight, it is given a health check before its release into various crèche sites throughout the South Island. These mainland and offshore sites are monitored for signs of predators to give the kiwi their greatest chance at survival.

Other conservation programmes

In Kaitiaki of the kiwi, discover more about the work undertaken since 1992 by the Lake Waikaremoana Hapū Restoration Trust to help protect kiwi in their area. Find out how a 9-year research project demonstrated that the predation of eggs and chicks was the main cause of kiwi decline – a very important discovery for future conservation planning.

Additional sanctuaries that help kiwi

In 2000, DOC set up five kiwi sanctuaries with the goal to increase the number of young kiwi surviving each year via predator control and to provide opportunities for research and monitoring. Three are in the North Island and two in the South Island. The sanctuaries are:

• Whangārei Kiwi Sanctuary (Northland brown kiwi)
• Moehau Kiwi Sanctuary on the Coromandel Peninsula (Coromandel brown kiwi)
• Tongariro Forest Kiwi Sanctuary near Taupō (western brown kiwi)
• Ōkārito Kiwi Sanctuary (rowi)
• Haast Tokoeka Kiwi Sanctuary (Haast tokoeka).

This intensive management programme has been rewarded with dramatic increases in chick survival rates – for example, at Whangārei, 50–60% of chicks survive their first 6 months compared with only 11% outside the sanctuary.

Other mainland conservation islands and fenced sanctuaries that have significant populations of kiwi and/or assist with kiwi conservation through programmes such as kiwi crèches include:

• ZEALANDIA, Wellington (little spotted kiwi)
• Maungatautari Restoration Project, Waikato (brown kiwi)
• Bushy Park Forest Reserve near Kai Iwi, Whanganui (brown kiwi)
• Otanewainuku Forest, Bay of Plenty (brown kiwi)
• Hurunui Mainland Island, south branch, Hurunui River, North Canterbury (great spotted kiwi)
• Cape Sanctuary, Hawke’s Bay (North Island brown kiwi)
• Rainbow Springs Nature Park, Rotorua (brown kiwi)
• Orokonui Ecosanctuary (Haast kiwi).

This conservation work also allows ongoing research into kiwi, for example, looking into behaviour patterns, genetics and more to ensure conservation efforts continue to be informed by the latest research.