North Island weka Gallirallus australis greyi

<span class=primary-name>North Island weka</span> <span class=secondary-name>Gallirallus australis greyi</span>
<span class=primary-name>North Island weka</span> <span class=secondary-name>Gallirallus australis greyi</span>
<span class=primary-name>North Island weka</span> <span class=secondary-name>Gallirallus australis greyi</span>
<span class=primary-name>North Island weka</span> <span class=secondary-name>Gallirallus australis greyi</span>

General information

Weka are a large, flightless rail that are only found in New Zealand. The range and numbers of the North Island sub-species were in decline late last century, but they are now thriving in many plantation forests. Weka can occupy a wide variety of habitats from rocky shores and sand dunes to subalpine grasslands.

Weka are fully protected on mainland NZ. They are about 50 centimetres long, with a strong tapered bill, sturdy legs and reduced wings. Depending on the subspecies and environmental conditions, male weka weigh around 1 kilogram and females 700 grams.

Weka are omnivorous, eating a variety of foods including, worms, lavae, beetles, snails, frogs, small birds and eggs and carrion. They predominantly eat plant foods including grass, leaves, berries and seeds – they are important seed spreaders, especially seeds too large to be spread by smaller berry-eating birds (e.g. hinau, pigeonwood and fuscia).

Weka are generally territorial and can breed year-round if food is abundant (up to four broods). Weka nest on the ground, usually in thick clumps of toitoi/rush type vegetation. On average, 3 creamy-pink eggs with violet/purple, brown speckles, are laid in a clutch (usually between August – December). The eggs hatch after four weeks, and the chicks are fed by both parents. Juveniles tend to leave the parental territories at between 40 and 105 days, when the parents are no longer interested in feeding them, or they have developed independent feeding methods. In good conditions, they can breed from eight months of age.

Threats

Weka are killed by harriers, dogs, cats, ferrets and stoats and can also be badly affected by lack of food during drought. Rats and hedgehogs can eat their eggs. Other introduced mammals (possums, rabbits, goats, deer and wallaby) also compete for their food sources by browsing forests and changing forest leaf litter composition. Many are killed by vehicles.

Weka are also affected by major changes to dense cover (e.g. vegetation clearance and loss of dense vegetation corridors).

Commercial Forestry and North Island Weka

Weka are relatively common in plantation forests in Eastern Bay of Plenty and inland Poverty Bay, and range freely through all forest age classes and cut-over areas.

As ground disturbing operations expose soil-based worms and insect larvae, weka will utilise operational sites when machinery is not operating. They also break down fallen logs to extract wood-based insect larva – an important food source in some forests. They also hide within slash and log piles.

Commercial Forest Management guidance:

  1. Determine if North Island weka are present (through direct sighting of weka, ecological surveys or evening/morning call surveys. Stream-based eDNA is likely to only be reliable when weka are in medium to high density in the area).
  2. Operational staff should be trained in weka identification (birds and nests/eggs and weka calls).
  3. Should a nest be identified, that would be affected by the mechanical removal of vegetation, a buffer of not less than 50 metres shall be placed around the nest until the chicks are at least two weeks old.
  4. Protect indigenous vegetation, including corridors and riparian habitat where weka are likely to forage and take refuge during harvesting.
  5. Allow weka time to move from under machinery when operations commence (recommended 30 seconds) and then drive off slowly.
  6. If rehabilitating slash piles, work slowly and carefully from the top of the slash pile to allow any weka time to vacate the slash.
  7. Weka can be trapped in headlights – dip the lights, slow your speed, and allow the weka to move off the road.
  8. Sightings of weka should be recorded in iNaturalist – Biodiversity in Plantations study.
  9. Never feed weka (including food scraps) – this will encourage them to come nearer to people.
  10. Report any weka injuries or fatalities to the DOC Hotline: 0800 DOC HOT/0800 362 468 (and within company reporting requirements).

Weka calls can be used as a survey for nesting

Paired weka give “spacing calls” mainly in the mornings and evenings. They are a characteristic “coo..eet” given as a duet by members of a pair, with the male call lower in pitch and slower than the female call. Weka warning squeaks are a single shrill note and given more than once when chicks are present. Other calls include quiet booming, and soft clucking contact calls.

How to undertake a call survey to determine if North Island Weka are nesting in an operational area

  1. Use any existing information to determine if weka are likely to be present.
  2. On a map of the operational area, identify accessible listening sites approximately 500 m apart, the radius of each site shouldn’t overlap.
  3. It is recommended to carry out a survey approximately four weeks before the operation starts.
    • In the morning from an hour before sunrise to half an hour after sunrise; or in the evening from an hour before sunset, to half an hour after sunset (i.e. a total of 1 ½ hours)
    • For each weka call, record the compass bearing, approximate distance and type of call (e.g. NNW, 150 m, pair duetting / individual)
    • Plot the locations of each weka call on the map. Note: multiple calls may be made by the same pair at the same site.
    • GPS each listening site for future reference.
  4. Repeat the survey just before the operation begins, using the same listening sites.
  5. If the pairs at a location change from giving duets to no calls, or just a single bird is calling, then these are the areas where nesting may be occurring.
  6. If weka were recorded from a previous survey, and the operational areas has not been used for greater than a month, it is recommended that the survey is repeated before recommencing operations to determine if weka are now breeding.

References