North Island weka Gallirallus australis greyi

North Island weka

Description

  • Weka are large, brown, flightless rails, approximately the size of a large chicken.
  • The territorial call of weka is a loud ‘coo-eet’ which is repeated. This is used to monitor the species’ presence and abundance.

Interesting Facts

  • The species is separated into four subspecies, only one of which is included here. The buff weka was introduced to the Chatham Islands and then became extinct within its natural distribution in eastern South Island. It remains plentiful on the Chathams and is legally harvested for food (At Risk-Relict). The Stewart Island weka is largely confined to offshore islands around Stewart Island where it has been introduced. On the main island, it has largely died out save for occasional reintroductions (Nationally Vulnerable). The western weka is relatively widely distributed on the West Coast, some populations being abundant, while others are sparse (Not Threatened).
  • The North Island weka has been considered Nationally Critical in recent years, but is now considered At Risk-Recovering. Strongholds in the North Island are Russell Peninsula, Kawakawa Bay (Auckland) and the Opotiki-Motu region in Bay of Plenty.
  • Weka that maintain territories close to human activities can become very bold and inquisitive.
  • If conditions are suitable, weka can breed prolifically, however populations are also known to suddenly crash.

Association with Plantations

  • Weka will use plantation forests if they are adjacent to more suitable areas such as indigenous forest remnants, wetlands, scrubland etc. They tend to be associated with margins - the area where one habitat type changes to another.
  • Research suggests that weka may prefer pine plantations to pasture areas.

Threats

  • The causes of the rapid declines seen during the early 20th century are not clear, but are likely to have been due to loss of forest and scrubland and the introduction of mammalian predators.
  • The removal of thickets and weed communities (such as gorse and blackberry) from riparian strips and forest remnants, the under-grazing of remnants, the burning of logs, and the spraying of weed species on farmland and roadside verges reduce suitable breeding and foraging habitat for weka in modified landscapes.
  • Major fluctuations in population numbers still occur and are poorly understood. The declines have often been attributed to disease, but may be due to food scarcity in some years causing reproductive and adult mortality.
  • Predation of eggs and young by possums, rats, hedgehogs and mustelids.
  • Predation of juveniles and adults by mustelids, cats and dogs.
  • Accidental mortality in leg hold traps. Research has shown that weka can jump to 700mm vertical height and climb a ramp set less than 38 degrees to the ground.
  • Accidental mortality in trapping tunnels that are not of sufficient length and/or are not double baffled.
  • Poison operations can have signficant effects on weka. Aerial 1080 operations appear to have minimal effect, but brodifacoum/Talon operations have major impacts and have been used to eradicate weka from islands where they have become a problem. Pindone, slug pellets and Timms traps can also cause problems for weka. Weka can often reach poison bait stations.
  • Droughts causing food shortages (which may become worse with climate warming).
  • Accidental death from motor vehicles.

Management Options and Methods

  • Similar methods to kiwi protection:
  • Habitat protection:
    • Protect indigenous vegetation, including corridors and riparian habitat where weka are likely to forage.
    • These areas will provide refuge during harvesting and access to other habitat areas.
  • Forest harvesting where weka are present:
    • Ascertain if they have escape routes to alternative habitat, especially indigenous habitat.
    • Stage harvesting to keep escape routes open for as long as possible.
  • Post-harvest:
    • Avoid grazing, burning or spraying in order to encourage recovery of vegetative cover and higher ground moisture levels.
    • Avoid disturbance of known weka habitat (i.e. slash piles) during land preparation.
  • Pest control:
    • Critical to exclude all dogs.
    • Implement alternative pig control methods, e.g. hunting without dogs, poisoning, trapping.
    • Work with local community and DOC towards exclusion of dogs from all weka areas.
    • Carry out mustelid and cat control.
    • Maintain possum numbers at moderate to low levels. (Undertake 1080 possum operations to provide maximum benefit to weka and other biota through secondary kill of predators (also consider benefits of integrated pest control to kereru and other species).
    • Maintain contact with DOC, councils, landcare groups and other groups to co-ordinate pest control.
    • If using Timms traps, set in evening and release in early morning.
    • Contact DOC for up to date advice regarding use of types of poison and methods of poisoning other than 1080 for control of pest species.
  • Injured or dead birds:
    • Place injured birds in a cardboard box (keep shaded) and deliver to a local vet, SPCA or DOC.
    • Call DOC if bird has a band, or bird is dead.

Monitoring Options

  • Monitor weka using standardised call counts carried out at dusk. Contact DOC for methods.
  • Report findings to DOC.

Further Information and Support