Pest Free Onetahua

This important pest control project spans from the tip of Farewell Spit to Whanganui Inlet, including the Kaihoka Lakes Scenic Reserve and Pākawau Forest in Kahurangi National Park.

Onetahua Restoration Project birds graphic

Why Onetahua?

Pest Free Onetahua is an ecological project of international significance. The dynamic and diverse landscape is like no other, with thousands of migratory birds and endangered flora and fauna calling it home. It is also of great cultural and spiritual significance to Manawhenua ki Mohua as o te wairua o ngā tangata o te Waipounamu – the place where the spirits depart.

This project lays a foundation for a thriving wildlife habitat rich in Māori traditions and ancestral stories. We will pave the way to return nature to Onetahua and create a safe haven for endangered bird species to thrive.

Onetahua/Farewell Spit is a landscape of international significance. A critical stopover for migratory shorebirds, it gained international status as a Ramsar site in 1976. Pests threaten many of these birds and the precious native species that make this place their home - we want them gone and we’re not alone. Pest Free Onetahua is part of a growing nationwide movement to remove pests and return these habitats to their rightful owners - our native tāonga.

White Fronted Terns on Farewell Spit - Photo Credit Bradley Shields

Photo by Bradley Shields

Shifting Sands and Changing Landscapes

A Place Shaped by Wind and Water

Onetahua continues to grow in both length and width thanks to quartz sand deposits originating in the Southern Alps. These are carried by rivers to the Tasman Sea and onto Farewell Spit by the longshore sea currents. Its elegant curve, reminiscent of the Kiwi’s beak, reaches into Tasman Bay as a result of this process, which began millions of years ago - most likely in the Pleistocene epoch.

Archaeological findings, including middens and pits, show the early Māori occupation of Onetahua. With the arrival of European settlers, Onetahua - or Tuhuroa as it was then known to local Māori - would undergo a dramatic transformation. A diary entry from HP Wasbourn in 1933 describes the spit as once being covered with vegetation, but thanks to slash and burn techniques and stock grazing, the area was stripped of its greenery.

A Precious Tāonga of International Significance

Established as a Ramsar site in 1976, Onetahua's significance is internationally recognised. The site is the highest ranked ecosystem in the Tasman District (Leathwick & Singer 2019). With 20,000 migrating wading birds calling this area home each summer, some flying from as far afield as Siberia, its importance as one of the largest bird habitats in the country is undeniable. Some 90 species of bird have been recorded here in this hugely dynamic and diverse environment.

Flying =Birds on Farewell Spit - Photo Credit Bradley Shields

Photo by Bradley Shields

Australasian Gannets - Photo Credit Bradley Shields

Photo by Bradley Shields

So What’s Wrong With This Picture?

Species such as the Banded Rail, Pipit, Marsh Crake and the beloved Little Blue Penguin, are all in decline. More seriously, the fate of the Australasian Bittern is considered critical. Others fluctuate between vulnerable and endangered. What makes the spit so attractive to birds, a cornucopia of molluscs, echinoderms, crabs and worms that reveals itself at low tide also provides a lure for predators. These food-rich tidal flats on the inner side of the Spit attract possums, pigs, mustelids and rats into the fragile nesting areas of defenseless birds. The effect of this predation has been devastating and conservation workers report regular sightings of plundered nests and rooted up vegetation.

It's Not Just About the Birds

Onetahua is also home to other native species. Powelliphanta and other carnivorous snails, endangered green geckos, skinks, carabid beetles and weta are also at risk of predation. Vegetation on the Spit is susceptible to grazing by possums who have also been causing damage to the Rāta in Pakawau Forest. Hares are intense grazers of young seedlings, and stop the regeneration of plant life.

What will we gain?

Removing the pests that threaten our precious native species will result in direct biodiversity benefits. Restoring Onetahua to a thriving wildlife haven will also strengthen our communities, our economy and our culture. We can play an important role in lifting our most vulnerable species from endangered to recovering - and engage our community and create valuable jobs for locals.

Our understanding of the link between pest eradication and climate change is growing. A Forest and Bird report shows the negative impact of browsing pests on the ability of native ecosystems to be carbon sinks. Stopping pests from stripping away this vegetation can help reverse this trend.

Many local landowners are already carrying out their own trapping in the area. HealthPost Nature Trust has a smaller scale trapping programme in place and Farewell Spit Eco tours have been actively trapping on the Spit for many years. Together we can tackle these pests, building on the hard mahi that’s already underway and share our learnings with other predator free projects across New Zealand.

Our Partners

Pest Free Onetahua is a partnership between Te Tauihu Environment Trust and Manawhenua Ki Mohua, working closely with DOC, HealthPost Nature Trust, local landowners and the Mohua community.