Marsh crake Porzana pusilla affinis

Marsh crake

Description

  • Spotless crakes are small birds about 20 cm in length. The species is very darkly coloured, with a black bill, strikingly red eyes, and orange legs.
  • It is largely confined to freshwater wetlands.
  • Marsh crakes are similarly-sized birds. The upper parts and wings are chestnut brown, the bill is green, and the face grey.
  • Marsh crakes are found in both freshwater and coastal wetlands.
  • Banded rail are slightly larger than the crakes, and intricately patterned. They are mainly olive brown, with white barring and a bold white stripe above the eye.
  • Banded rail are largely confined to coastal wetlands.

Interesting Facts

  • The three species are all highly cryptic and rarely seen. Marsh crakes are the least reported of the three species.
  • Banded rail are often monitored using footprints. All species can be monitored using audio playback of their calls.
  • Spotless crakes are widespread in the North Island, but are very rarely reported from the South Island.
  • Marsh crakes may be more common in the South Island than the North Island, but records are rare, and it is generally recorded much less than spotless crakes.
  • For many years, the populations of both species have been considered to be relatively stable. However, in 2017 the classifications of both species were changed to At Risk-Declining.
  • Banded rail has a disjunct distribution, only being recorded in the North Island, from the Waikato and Bay of Plenty northwards, and from the top of the South Island. However, it is also known from a few islands off Stewart Island, and is sometimes infrequently recorded in other regions such as the Wairarapa and Taranaki; these birds may mainly be dispersing juveniles.
  • All three taxa are also known outside of New Zealand.
  • Spotless crake is known to inhabit dry forest on some predator-free offshore islands, suggesting it once survived in different habitats other than freshwater prior to habitat clearance and the introduction of predators.
  • The actual impact of predators on all three species is unknown as all are poorly studied.
  • All wetland birds require high quality wetland habitat buffered from the effects of surrounding land management.

Association with Plantations

  • Wetland birds are found in many plantation forests.
  • Wetland birds may be hard to detect due to their elusive behaviour.

Threats

  • Habitat loss and degradation from wetland drainage, loss of riparian margins, and the effects of surrounding landuse.
  • Invasion of exotic plants, which can seriously modify wetlands and reduce suitability for birds.
  • Disturbance and motor wash from recreational boats
  • High predation rates, particularly of pateke, mainly from dogs, cats and mustelids.
  • Mammalian predation may also affect some other wetland bird species, but the extent of the impacts is unknown.

Management Options and Methods

  • Habitat protection:
    • Protect important wetland habitats and riparian buffers.
    • Avoid using herbicides or pesticides close to wetlands.
    • Ensure weeds are not inadvertently introduced to wetlands, e.g. via machinery or boats.
    • Consider control options for existing, invasive, wetland weeds.
    • Consider a staged removal of willows to ensure ongoing cover for crakes and ducks.
  • Forest operations:
    • Minimise damage to riparian and wetland habitat during road construction and harvest operations.
    • Avoid grazing wetlands and their margins. Fencing may be appropriate in some situations.
    • Avoid diverting run-off into wetlands.
    • Minimise disturbance during spring breeding.
    • If pateke are present, discuss predator control with neighbours and DOC.
  • Injured or dead wetland birds (particularly the more threatened species, i.e. white heron, bittern and pateke):
    • Place injured birds in a cardboard box (keep shaded) and deliver to a local vet, SPCA, DOC.
    • Call DOC if bird is dead.

Monitoring Options

  • Increase staff and contractor knowledge about wetland birds.
  • For important wetlands that are likely to have the more threatened species, consider undertaking a bird monitoring programme:
    • Counts of pateke flock sites in late summer.
    • Fernbirds, spotless crakes and to a lesser extent marsh crakes and banded rails respond to taped playback calls.
    • The booming calls of bittern are characteristic at dusk in September-October particularly during bright moonlight.
  • Maintain a database of sightings.

Further Information and Support