The Weka or woodhen (Gallirallus australis) is a flightless bird species of the rail family. It is endemic to New Zealand, where four subspecies are recognized. Weka are sturdy brown birds, about the size of a chicken. As omnivores, they feed mainly on invertebrates and fruit. Weka usually lay eggs between August and January; both sexes help to incubate. Tales of Weka stealing shiny items and bags of sugar are part of New Zealand folklore.
Weka are predominantly rich brown mottled with black and grey; the brown shade varies from pale to dark depending on subspecies. At over 50 cm long, the male is about 1 kg and the female is about 700 g. The reddish-brown beak
is about 5 cm long, stout and tapered, and used as a weapon. The pointed tail is near-constantly being flicked, a sign of unease characteristic of the rail family
. Weka have sturdy legs and reduced wings.
Taxonomy and distribution
The common name Weka is a Māori
word. The species was named Rallus australis
by Anders Erikson Sparrman
in 1789. Sparrman published the information in Museum Carlsonianum
, four fascicules based on specimens collected while voyaging with Captain James Cook
between 1772 and 1775. Australis
is Latin for "southern". Johann Georg Wagler
's suggestion of the Ocydromus
genus in 1830 to describe each Weka as a species was generally adopted. However, Weka were later decided as a single species in the Gallirallus
genus with four subspecies.
The Buff Weka (Gallirallus australis hectori) formerly inhabited the eastern districts of the South Island but is now confined to Chatham Island and Pitt Island to which it was introduced in the early 1900s, and where they are widely hunted and eaten, being considered 'introduced'. Reintroduction into Canterbury has been unsuccessful so far. It has a lighter overall colouring than the other subspecies. The North Island Weka (Gallirallus australis greyi) is represented by original populations in Northland and Poverty Bay, and by liberations elsewhere from that stock. This subspecies differs in its greyer underparts, and brown rather than reddish coloured legs.
The Western Weka (Gallirallus australis australis) is found mainly in the northern and western regions of the South Island from Nelson to Fiordland. Distinguished by dark red-brown and black streaking on the breast, the Western Weka has two distinct colour phases, that of the southernmost range showing a greater degree of black. The Stewart Island Weka (Gallirallus australis scotti) is smaller than the other subspecies and, like the Western Weka, has two colour phases; a chestnut form - similar to the chestnut-phase Western Weka - and a black phase which is not as dark as the black Western Weka. The population is confined to Stewart Island and outliers, and to Kapiti Island to which it was introduced.
Habitat and diet
Weka occupy areas such as forests
grassland, sand dunes
, rocky shores
and modified semi-urban environments. They are omnivorous, with a diet comprising 30% animal foods and 70% plant foods. Animal foods include earthworms
, grass grubs
, insect eggs
, and small birds
. Plant foods include leaves
. Weka are important in the bush as seed dispersers, distributing seeds too large for smaller berry-eating birds. Where the Weka is relatively common, their furtive curiosity leads them to search around houses and camps for food scraps, or anything unfamiliar and transportable.
Breeding and nesting
The breeding season varies, but when food is plentiful, Weka can raise up to four broods throughout the whole year. Nests
are made on the ground under the cover of thick vegetation, and built by making grass
(or similar material) into a bowl to hold about four eggs
. On average, female Weka lay three creamy or pinkish eggs blotched with brown and mauve. Both sexes incubate. The chicks hatch after a month, and are fed by both parents until fully grown between six and ten weeks.
Weka are classed as a vulnerable species
. The Department of Conservation's
Weka recovery plan, approved in 1999, aims to improve the conservation status of threatened Weka, clarify the status of data deficient Weka, maintain the non-threatened status of other Weka, and eventually restore all Weka to their traditional ranges as a significant component of the ecosystems.
Weka are problematic in conservation; some subspecies are threatened, but have been a problem to other threatened wildlife on offshore islands, especially when introduced to an island that they would not naturally inhabit. Weka are unable to withstand the current pressures faced in both the North Island and South Island. However, they can be very productive in good conditions and high food availability. Year-round breeding has been recorded at several sites with up to 14 young produced in a year. Weka populations can persist in highly modified habitats, but they have disappeared from huge areas of their former range, suggesting that they can adapt to a wide range of conditions but are particularly vulnerable to threats.
The Department of Conservation
identifies eight main threats to Weka. Predation
, cats and dogs are a threat to adult Weka; stoats
, ferrets are a threat to chicks; stoats and rats
are a threat to eggs. It faces competition with introduced species for fruits and invertebrates, and suffers from the impact browsers have on forest composition and regeneration. Habitat depletion is caused by the modification and degradation of forests and wetlands. Diseases
have been associated with population declines, although little is known. Drought
has been implicated in the disappearance of Weka from some areas. In some regions, motor vehicles
cause a significant amount of roadkill
death. Pest control operations sometimes kill Weka, as they have ground foraging habits vulnerable to poison baits, and traps are laid in a way that Weka can reach. Genetic diversity
can be lost during the transmission of genes through generations, affecting isolated populations.
Human interaction and folklore
Weka are significant to some Maori iwi
who admire their curiosity and feisty, bold personality. These also led to them being relatively easy to catch. Weka were used by the Maori as a source of food, perfume
to treat inflammations
in clothing and lures to catch dogs. Early European explorers and settlers frequently encountered and utilised Weka, who gave them the name "bush hen".
Tales of Weka stealing shiny items and bags of sugar are part of New Zealand folklore.
Notes and references
- Database entry includes justification for why this species is vulnerable
- Penguin Pocket Guides: New Zealand's Native Birds of Bush and Countryside. Pages 76-77. 1996. Published by Penguin Books. ISBN 0-140-26010-2