Estuarine Wetlands

Auckland used to have extensive wetlands, both freshwater and estuarine, but most of these have been drained and filled, and in Auckland City, mostly reclaimed and developed.

A few coastal estuarine wetlands remain unmodified; and two of these F&B has been and still is involved with -Tahuna Torea on the Tamaki Estuary, and Pollen and Traherne Islands in the Motu Manawa Marine Reserve in the Upper Waitemata Harbour.

Estuarine wetlands are very important, because they are responsible for:

  • providing flood control, stabilising shorelines and protecting against storms
  • providing nurseries and habitat for juvenile marine organisms
  • supporting a wide range of native plants, including many threatened species
  • retaining nutrients and sediments
  • supporting biological diversity
  • reducing erosion and nutrient run-off
  • providing nesting and feeding areas for birdlife, including many migrating birds that visit New Zealand each year or fly up from the South island as part of their annual lifecycle, and many endangered bird species (wetlands are home to 22% of New Zealand’s birds)
  • storing carbon and mitigating effects of climate change
  • creating tourism and recreation opportunities (for example for bird watchers, walkers, and photographers).

The plant species occurring at these wetland areas is dominated by mangroves, low-growing shrubs and native grasses. For a fuller detail of species, refer to the external documents listed on the page on this website about Motu Manawa reserve.

Traherne Island (Photo Kent Xie)

We work to protect the few un-modified or restored estuarine wetlands left in Auckland City.

While there are no unmodified freshwater wetlands remaining, a few are being restored, like Western Springs and Waiatarua Reserve.

For more information about wetlands, click here, and for information about recreating a wetland, click here

Fernbird (Matata) - a bird of high importance to MotuManawa Marine Reserve

This endemic, once widespread and abundant bird of wetlands and low tangled scrub urgently deserves more public attention.

About 18 cm in length, the fernbird is rich brown above, paler below, and heavily streaked and spotted dark brown over the throat and breast. The forehead and crown are chestnut and there is a white eyebrow stripe. Half of the bird’s length is made up of frayed-looking brown tail feathers, which it droops characteristically when in flight.

Although the fernbird is known as a weak flier, juveniles do travel (not a great distance) to set up new territories.

Fernbirds live in pairs and from their dense scrub habitat typically call out to each other in a duet, making a high-pitched, metallic “u-u-u tic, tic” sound. The call is particularly well synchronised.

The fernbird mainly feeds on small insects and both parents feed the chicks.

It is a shy and secretive bird, but this habit of hiding away from threats is probably what has enabled it to survive against horrendous odds where other New Zealand endemic bird species have fallen by the wayside. Sadly its Chatham Islands cousin Bowdleria rufescens is believed to have become extinct around 1900 thanks to bird collecting and habitat destruction.

Although given to hiding, fernbirds are naturally curious and when you click small stones together or mimic their high pitched calling sound in their habitat, they will often poke their heads out of the scrub to have a look and then quickly disappear again.

Maori knew the fernbird as “the wise bird” because of it’s ability to warn them about impending troubles or foretell good fortune depending on how its cry changed (

We owe the fernbird a huge debt of gratitude because when government land was being transferred to the then new Department of Conservation, fernbird presence was often the one criterion that allowed wetlands to be conserved.

Nearly 90% of New Zealand’s wetland area has been lost since the early 1800s, and many remaining lakes and wetlands are degraded from the effects of farming: burning, wetland drainage, chemical spraying, and fertiliser runoff from surrounding farmland.

Because of it's importance, fernbird has been chosen as the bird species recently rediscovered to be living still in the MotuManawa marine reserve, to be a main indicator of this wetland's health.