Saturday, December 25, 2010

The New Zealand Weka

I've been really enjoying seeing Weka around places I visit in the South Island.  Until February this year, I had never seen one at all.  Just before I came across on tthe ferry, I visited a sanctuary in the North Island near Levin, and saw a North Island Weka for the first time.  Since I've been in the South Island, I've seen them in the wild now on three occasions.

There are (or have been)  four types of Weka in New Zealand,  one is now extinct, and the other are on the 'threatened' list.  Each one is slightly different.  The South Island one I have seen is the Western Weka and is mainly brown, and the North Island is described as more grey - but I thought they had more teal colours than grey...

The Weka or woodhen is a flightless bird species of the rail family and are endemic to New Zealand. They 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.

The Buff Weka 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. I haven't seen any so can offer no photograph here!

The North Island Weka 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  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 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/Rakiura and outliers, and to Kapiti Island to which it was introduced.

Weka occupy areas such as forests, sub-alpine 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, larvae, beetle, weta, ants, grass grubs, slugs, snails, insect eggs, slaters, frogs, spiders, rats, mice and small birds.  Plant foods include leaves, grass, berries and seeds. 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. Which is probably why they came running when we stopped by the side of the road, hoping to swipe some food off us.

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. Chicks are fed by both parents until fully grown.

 Weka are classed as vulnerable. 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.

Doc has identified eight main threats to Weka. Predation by ferrets, cats and dogs are a threat to adult Weka. Stoats, and 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 and parasites 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.

Weka are curious and feisty, with a bold personality. This leads to them being relatively easy to catch. Weka were used by the Māori as a source of food, perfume, oil to treat inflammations, feathers 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.


Amelia said...

I was away on camp at the begining of the year and the rangers told us not to leave any possesions lying around (shoes!). Me, Being the happy go lucky person I am totally disregarded this statment as a joke. To my misfortune one of these curious critters (I suspect)came in the night and Stole the shoe laces out of my runners!!! needless to say i paid much more attention to the warnings of the rangers and keeped all my shoes inside!! =)

Robyn said...

I reckon they would be fun birds to have around :)

Morgan said...

The are incredible looking birds. Nice capture of them!

Robyn said...

I think they look like miniature Moa's!

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ozpest said...

Weka strange looking birds

Fred said...

Nice close up photo work.