There are three distinct geographical forms, known as taxa:
- Haast tokoeka
- Fiordland tokoeka
- Rakiura (Stewart Island) tokoeka.
Except for Haast tokoeka, the other two taxa are generally larger than brown kiwi, and some can grow as big as the great spotted kiwi.
All population numbers quoted are based on 2015 estimates unless stated otherwise.
The combined population numbers for the three tokoeka taxa make it the most numerous kiwi species in New Zealand – 25,900.
However, the Haast tokoeka, a mountain-loving kiwi, is New Zealand’s rarest taxa, with an estimated population of just 400.
The most abundant taxa is the Rakiura (Stewart Island) tokoeka, with an estimated population of 13,000. This is a 13% decline from the 2008 population estimate.
The table below shows 2008 and 2015 estimates for the three tokoeka taxa, and what they could be in 15 years time. It assumes a decline of 1% each year for the Fiordland tokoeka, an annual decline of 1.8% for the Rakiura (Stewart Island) tokoeka, and an annual increase of 4.2% for the Haast tokoeka, which is very actively managed through Operation Nest Egg and a 6000-hectare stoat trapping programme. At present, 80% of Haast tokoeka are under active management. By contrast, only 8.8% of the Fiordland taxa is under active management, and only 1.9% of Rakiura birds are actively managed.
|Region||Estimated 2008 population||Estimated 2015
|Rakiura (Stewart Island)||15,000||13,000||9,962|
As with other kiwi species, all tokoeka taxa usually have just one mate, and mate for life. If its partner dies a bird will re-mate.
Rakiura (Stewart Island) tokoeka differ from most other kiwi species because they can live in large family groups, with an alpha male and female. Their sons and daughters stay around as helpers until a vacancy arises in a nearby territory, allowing them to disperse.
Eggs and clutches
Fiordland tokoeka and Haast tokoeka usually have just one egg in a clutch and one clutch each year. Birds that are part of Operation Nest Egg will have two clutches in a season, which means it is likely that a pair will re-lay if it loses an egg to a predator.
With Rakiura (Stewart Island) tokoeka, because they live in family groups with helpers available, it is not unusual for breeding pairs to have two clutches in a season.
Haast tokoeka pairs share the incubation, with males doing about 60% of the egg sitting.
Rakiura (Stewart Island) birds are unique among kiwi because young birds help with incubation, sitting on the egg for up to 20% of the time. The alpha pair shares the remaining incubation time equally. The female takes the night shift, which is why female birds are often seen during the day.
Theories about why the Rakiura (Stewart Island) birds are different include the effect a colder southern climate may have had in their evolution, especially during ice ages when birds would have stayed together for warmth. The North Island would have been milder, allowing kiwi living there to have more eggs and more clutches each year. Another theory is that staying together provided defence against ancient predators, such as the goshawk and giant eagle.
Except for Haast tokoeka, tokoeka chicks stay with their family unit. On Rakiura (Stewart Island), this can be for up to seven years.
For Haast tokoeka, chicks are independent after about one month.
Operation Nest Egg
Operation Nest Egg is used only for the critically endangered Haast tokoeka.
Kohanga kiwi populations have only been established for Haast tokoeka. You can read about them here.