Reversing the Red on the rowi kiwi

Rowi (Apteryx rowi) are the rarest of the five species of kiwi. 
There is one natural population of about 450 rowi in Ōkārito forest and surrounds in South Westland. Rowi can also be found on two predator-free islands in the Marlborough Sounds, following successful translocations of birds.


Measuring Success through Assess/Plan/Act: 

Before human settlement of New Zealand, rowi were widespread throughout the northern South Island and into the southern North Island, as far north as Lake Poukawa (Hawkes Bay).

Rowi have now disappeared from their range in the southern North Island and northern South Island. Up until the 1990s, they were declining due to recruitment failure caused by predation of chicks and juveniles by stoats, and some adults being killed by dogs and motor vehicles. By far, the biggest threat to rowi survival is stoats.

Assess:

Through predation and habitat loss, these remarkable birds have been reduced to just one natural population and are classified by New Zealand’s Department of Conservation as “Nationally Endangered”.

Plan:

Roughly 80 rowi eggs are laid each season, 40 of these eggs fail to even hatch. Of the remaining 40, 28 are killed by stoats, and about 8 die of natural causes or killed by other predators. This leaves just 4 chicks alive after the first 6 months. Of these 4 chicks, only 2 will survive over 1 year to make it to adulthood.
However, using Operation Nest Egg the number of birds to make it to adulthood rises from 2 to approximately 50 per season. 

Act:

Operation Nest Egg involves removing eggs from the risk of predation, hatching them in captivity, and placing the chicks in a predator free environment until they are big enough to fend for themselves (between 1 to 1.2 kg). They are then returned to the wild.

Operation Nest Egg began with rowi in the mid-1990s. Before the Okarito kiwi sanctuary was established, nearly 70 Operation Nest Egg birds had already been released there. It is expected the tool will continue to be used for 5–10 years, until the population is large enough and other ways to manage it become more cost effective.


Results:

Rowi are a particularly powerful success story for Operation Nest Egg. In fact, the tool is credited with helping save the species from extinction.
Intensive management by the Department of Conservation (DOC) means the rowi population is no longer declining, but with so few birds they remain very vulnerable.


Key partners / stakeholders:

  • Te Rūnanga o Makaawhio and Ngāi Tahu
  • Department of Conservation
  • The Kiwi Recovery Group
  • Willowbank Wildlife Reserve
  • Westcoast Wildlife Centre 
  • Air New Zealand
  • Save the Kiwi
  • E-Ko Tours

 

Community involvement:

A dedicated group of volunteers carry out pest control on Kaipupu Point, used as a creche in the Marlborough Sounds.

 

Leveraging national and regional networks to facilitate success:

Zero Invasive Predators (ZIP) are currently planning a large landscape predator control operation in the Okarito kiwi sanctuary. Zero Invasive Predators (ZIP) was established to develop operationally ready, innovative, strongly supported technologies to completely remove rats, possums and stoats from large mainland areas, and then protect those areas from reinvasion.

 

Measuring Success:

The five-yearly census in 2021 counted 863 pairs. This was an increase of 305 pairs since the 2016 census and 565 more pairs since 2011.

 

Future plans for intervention:

Using the latest monitoring technology, we can keep a close eye on rowi. DOC has worked with a private business to develop ground-breaking technology specifically for our kiwi conservation work.

To track rowi, transmitters are attached to their legs. By monitoring the bird’s activity levels, these intelligent transmitters tell us where the bird is, when an egg is laid and when a chick hatches.

A system for data collection (nicknamed ‘Sky Ranger’) involves a program fitted to a fixed wing plane that flies over the forest searching for signals. This means transmitter signals, that might have taken 45 days of groundwork to complete, can now be gathered during a two-hour flight. The information collected lets us know what pairs are incubating and when we should collect the egg.

 

Reference: Story adapted from Department of Conservation Website - https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/kiwi/rowi/