CanterburyNature

Nestor notabilis

Written by Yena Woodside (Lincoln University)

July 2005

Edited by Michael Hudson, Lincoln University, September 2006

Taxonomy

• Scientific name: Nestor notabilis (Gould)
• Popular Common names: Kea
• Other common names: Mountain parrot

• Kingdom: Animalia
• Phylum: Chordata
• Class: Aves (the birds)
• Order: Psittaciformes (the parrots, cockatoos, lories, and lorikeets)
• Family: Psittacidae (the parrots)

• New Zealand Status: native (endemic)

• Taxonomy sources: Higgins et al. (1999), Temple (1996), Diamond & Bond (1999).

Identification

Species Description

To most New Zealanders especially South Islanders, the kea is one of the most well known and one of the most easily recognised native birds. They are familiar with its green coloured feathers, orange colour under its wings and its distinctive character. The kea is a large built parrot normally with body length of 46 – 50 cm; it has broad wings and a short tail (Higgins et al., 1999). It has a similar build to the kaka (Nestor meridionalis), which is genetically similar to the kea. However the kea is slightly larger (Temple, 1996). The kea has mostly olive-green coloured feathers with dark scaling; the feathers on its head and neck are darker than that on its chest and belly and even brighter green on its back and wings (Temple, 1996) (Figure 1). One of the most distinctive features of the kea is the bright orange-yellow coloured feathers on the undersides of its wings. In addition mature keas have brown cheeks.

Beak size differs between the male and female kea (the male having the larger); however the reason for this is not known (Temple, 1996).

According to Temple (1996) the kea is named after its in-flight call; which sounds ‘kee-a’. However, there is a much wider variety of communication calls between kea pairs.

Similar species

Most people should have little problem recognising the kea, however some confuse it with the kaka. The kaka has a smaller and lighter body than the kea, however the best way of distinguishing them is by their different colouring. The colour of kaka feathers appear less green and more red than the kea. The kaka also has a pale grey to white coloured area on its head and is heavier-beaked (Higgins et al., 1999). Additionally the call of the kaka is more ‘melodious’ and ‘whistling’ than the call of the kea (Temple, 1996).

Geographic Distribution

Full natural and naturalised range

The species Nestor notabilis is endemic to New Zealand and is not naturalised in other parts of the world (Diamond & Bond, 1999; Higgins et al., 1999).

New Zealand range

Nestor notabilis do not have a wide distribution across New Zealand. Mainly confined to the mountainous regions of the South Island, the kea is only occasionally found in the North Island (Higgins et al., 1999). Living throughout the Southern Alps the kea can be found from the St. Arnaud and Raglan ranges in the north, to the Humboldt Mountains in the south. In addition kea can also be found in Fiordland, north-west Nelson (Golden Bay) and in the seaward Kaikoura Mountains (Temple, 1996).

Before human settlement in New Zealand the keas home range included the North Island mountain ranges. The last North Island sighting was reported in the twentieth century (Temple, 1996).

Canterbury range

It is not difficult to find a kea in Canterbury, with a relatively large population throughout Arthur’s Pass National Park on the way to the West Coast. It is possible to see them when you go through and stop at the look out at the viaduct (personal observation).

Natural History in Canterbury

Habitats

The natural and favoured habitat of the kea is closely related to potential food sources. As suggested by the title of ‘mountain parrot’, keas can be found in vegetation at the higher altitudes of mountain regions; usually only to within 500 metres either side of the bush-line. However, the curiosity of the keas has also led them to our ‘civilised’ zones such as ski-field, huts and mountain villages (Temple, 1996).

The natural range of the kea is from sea level up to 2000 metres in the Southern Alps (Temple, 1996).

Preferred habitats

Most of the time keas prefer to stay in forests. Sometimes found inhabiting the silver beech (Nothofagus menziesii) forest beside the river and mountain beech (Nothofagus solandri var. cliffortoides) on the higher mountain slopes in Upper Maruia Valley, St James Walkway, North Canterbury, keas can also be found inhabiting the native broadleaf /podocarp forest which are home to totara (Podocarpus totara), miro (Podocarpus ferrugineus), rata (Metrosideros sp.), kamahi (Wenmannia racemosa) or Dracophyllum and more. Keas can sometimes be seen in more open spaces near the edge of the forest. These can include grass and scrub found on river flats and banks; or sometimes even in pasture (Higgins et al., 1999).

Modern day habitat use of the kea has changed significantly. Now they are frequently seen out of their natural habitats as they venture into ‘civilised’ zones. Places like ski-fields, mountain huts, camping grounds, car parks and rubbish tips (Higgins et al., 1999).

Phenology/Breeding

The breeding season for the kea occurs between July and January (Wilson, 1990). According to a previous study by K-J Wilson (1990), most eggs are laid in July or August with the eggs within a single clutch having been laid over several weeks (Higgins et al., 1999). Breeding cannot occur until a kea reaches sexual maturity at the age of about four (Temple, 1996).

Nests are made at ground level. Usually on north-facing mountain slopes, the nests are located in dry, well-drained areas within a natural hollow. The location of a nest could also be near something distinctive, for instance, a dead tree, exposed tree roots or a large rock. Male and female keas look for a place to nest together and they may even use the same nest they have used in previous years (Higgins et al., 1999). Reused nests are cleaned out and rebuilt each year (Temple, 1996). The female kea spends a lot of time lining the nest with soft lichens, dry moss, leaves and even small pieces of rotten wood.

With a maximum clutch size of four, the female kea lays one egg every two days.. According to an early study by K-J Wilson (1990), the female kea does the incubating and leaves the nest only to get food from her mate. Incubation usually takes three weeks or more (Temple, 1996). Another interesting feature is that the male kea never enters the nest; if the female is out foraging for food, he will wait outside the nest for the female to return in order to pass on the food he obtained for the chicks (Wilson, 1990).

Keas can be classified as K-selected, which means they generally live in stable populations and the size of the population usually remains constant (Wilson, 2004).

Diet

The main diet of the kea are plants found in alpine areas 500 meters either side of the bushline. They will eat any part of a plant and will eat many different species. Important food sources for the kea are the berries of both Coprosma and Cyathodes species and also snow totara (Podocarpus nivalis) of the sub-alpine areas. The seeds and leaf buds of mountain beech trees (Nothofagus solandri var. cliffortioides) and silver beech (Nothofagus menziesii) are another important food source (Temple, 1996).

Keas are omnivorous but they mostly have a vegetarian diet. However, when the opportunity arises they will not hesitate to eat insects or even bird eggs. When hungry the kea will often forage for food among human rubbish. In addition keas will frequently attend car parks in mountain area because it can be very easy to obtain food from humans (Temple, 1996).

Behaviour

Viewed as a playful bird, keas are curious and intelligent. Frequently playing in the air, they practise attacking and defending each other in strong mountain gusts (Temple, 1996). Keas have been seen sliding down slopes of snow, hut roofs and car windscreens. They often play with any object they happen to find (Higgins et al., 1999). By the time keas mature they have acquired great expertise in their mountain environment.

Longevity

Few keas die of old age. Because of the harsh conditions they live in, only a small percentage of keas in the wild could reach an age of about 15 years old. Most will die of starvation (Temple, 1996).

Dispersal

Keas are strong, direct and versatile fliers. Generally, they can make a 15 to 20 km flight between valleys in less than half an hour; and they can descend from snowline to valley floor within minutes. Having the ability to ride mountain winds and up draughts, the kea can rapidly gain both height and distance (Temple, 1996).

Predators

Since human settlement and the introduction of exotic animals, there have been negative effects on the native bird species of New Zealand in general. A lot of species have been driven to extinction. The main predators of the keas perhaps are the stoats (Mustela erminea) and possums (Trichosurus vulpecula). Both of these introduced species were found to have reduced kea populations and increased the likelihood of extinction considerably (Elliott & Kemp, 2004). According to Elliott & Kemp in St Arnaud Range, eggs and chicks missing from their nests were accompanied by clear signs of stoat predation. On the other hand, possums are also known to be nest predators; including kea nests. However keas nests are mostly sited near the tree line where possums are relatively rare. The graphical relationship prepared by Elliot & Kemp (2004) of sequential human, stoat and then possum population increases suggest corresponding negative impacts on kea numbers (figure 2).

See Elliott & Kemp (2004, http://doc.govt.nz/upload/documents/science-and-technical/dsis181.pdf) for a useful schematic representation of the likely chronology of kea decline and its relationship to hunting pressure and the colonisation of stoats and possums.

Parasites

There are many parasites that affect keas, such as mites (Arachnida), lice (Phthiraptera), internal threadworms (nematodes) and also a flea (Siphonaptera) called ‘the kea flea’ which will infest the nests of keas.

Mutualisms

Keas regularly eat fruit, chewing and cracking large seeds with their powerful beaks. Dispersal occurs in plant species that produce smaller seeds, for example, Coprosma pseudocuneata (Clout & Hay, 1989).

How to find the Kea

There are three types of places you could find a kea: mountain slopes with silver beech or mountain beech forest, tussock river flats within the Southern Alps and also on rocky/snow covered mountain sides. The best time is probably early or late in the day when they are feeding (Temple, 1996). However, keas are threatened so you should not set your expectations of sighting one too high. You may hear and see them flying above you in mountainous regions. If you are lucky they can be fearless; sometimes to the extent where they will play around humans and their equipment, often breaking things (Marriner, 1908).

Abundance and Conservation Status

• New Zealand: threatened
• Canterbury: threatened

The keas are a category B threatened species (Higgins et al., 1999).

Upsetting many sheep farmers, the keas were first reported feeding on dead sheep, and sometimes even attacking live sheep, in the late 1860s. Since 1870 about 150,000 keas have been killed. Most of these deaths were by shooting or poisoning. At the time farmers were allowed to hunt kea. After such a significant impact on the population, keas were fully protected in 1986 (Higgins et al, 1999). There are no official figures for current kea numbers; estimates for the recent population range from 5,000 to 15,000 (Temple, 1996). [Or as low as 1,000 to 5,000 (as suggested on the Department of Conservation website: editors comment).]

Significance for people

Traditional Maori significance and uses

When the Maori arrived in New Zealand they sought the kea for their feathers; however the kea was relatively safe in the mountain regions where only small groups of Maori would venture (Temple, 1996).

At the same time Maori also helped the kea with the deaths of the giant Haast eagle and goshawk, both natural enemies to the kea, as a result of the extinction of Moa (Dinornithiformes) (Temple, 1996).

Modern Uses

The kea is a protected native bird and thus cannot be harmed in any way. However, because of its character it is a precious and an entertaining bird to people who appreciate native birds.

Summary

The kea is an intelligent and an entertaining bird of great curiosity. Most New Zealanders, especially South Islanders, will be familiar with the kea. Being the only ‘alpine’ parrot in the world, N. notabilis only appear in South Island mountain regions. Its curiosity has led them to join in our ‘civilised’ zones and quite often share our food. It is not difficult to find a kea around the mountainous areas of Canterbury, such as Arthur’s Pass National Park. Next time you drive past, make sure to stop at the viaduct look-out; there is a chance that you will see the kea. However, it is important not to feed them.

References

Clout, M. N. & Hay, J. R. (1989). The importance of birds as browsers, pollinators and seed dispersers in New Zealand forests. New Zealand Journal of Ecology. 12 (Supplement), 27-33.

Diamond, J. & Bond, A. B. (1999). Kea, bird of paradox: the evolution and behavior of a New Zealand parrot. University of California Press, Berkeley, California.

Elliott, G. & Kemp, J. (2004). Effect of hunting and predation on kea, and a method of monitoring kea populations: Results of kea research on the St Arnaud Range. Department of Conservation, Wellington, New Zealand.

Higgins, P. J. (Ed.) (1999). Handbook of Australian, New Zealand & Antarctic birds (Volume 4). Oxford University Press, Melbourne, Australia.

Marriner, G. R. (1908). The kea: a New Zealand problem. Marriner Bros. & CO., Printers & Publishers, Christchurch, New Zealand.

Temple, P. (1996). The book of the kea. Hodder Moa Beckett Publishers Limited, Auckland, New Zealand.

Wilson, K. J. (1990). Kea, creature of curiosity. Forest & Bird Magazine, 21, 20-26.

Wilson, K. J. (2004). Flight of the Huia: Ecology and conservation of New Zealand’s frogs, reptiles, birds and mammals. Canterbury University Press, Christchurch, New Zealand.

Web based resources

Kea Conservation Trust
www.keaconservation.com.

Search for Nestor notabilis in New Zealand science online

New Zealand Journal of Ecology articles containing Nestor notabilis.

Search NZ Royal Society journals for articles containing Nestor notabilis.

Notornis articles (from the Ornithological Society of New Zealand) containing Nestor notabilis.