Data suggests kiwi are not great travellers
Specially-trained species conservation dogs used to sniff out kiwi in the Maungataniwha Native Forest, just south of Te Urewera, are finding a large proportion of unidentified adults, indicating that that intensive and ongoing predator control efforts there are proving effective.
38 adult birds have been found by specially-trained dogs since 2015. Of these, 22 were not microchipped.
Predators typically ensure that only about five percent of kiwi chicks survive to adulthood without human intervention. A large proportion of unidentified adults in the conservation area at Maungataniwha suggests that juveniles there may be hatching and surviving to adulthood naturally in the forest.
The Maungataniwha Kiwi Programme run by the Forest Lifeforce Restoration Trust (FLRT) is one of the most prolific and successful kiwi conservation initiatives in the country and part of the national kiwi breeding programme known as Operation Nest Egg. Adult male kiwi are fitted with radio transmitters to enable volunteers to retrieve their eggs, which are then taken for artificial incubation. The resulting chicks are raised in a special crèche or captive facility until they are large enough to fend for themselves in the wild.
Over 11 seasons between 2006 and April 2017 the Maungataniwha Kiwi Programme has released 184 kiwi back into the forest. All these young kiwi have been microchipped so that they can be identified.
Ms Ward-Smith said the high proportion of unchipped kiwi being captured was exciting because it demonstrated conclusively that Operation Nest Egg helps to grow a population of kiwi in places where numbers were previously in decline. It also shows that a good number of kiwi are surviving naturally.
The un-chipped kiwi may be old birds or young ones that have hatched and survived without human intervention. Either way it proves that predator control efforts are working too, she said.
Also of interest to the FLRT team is that the capture work has revealed that kiwi may not be particularly adventurous; none of the juveniles returned to the forest over the past 11 years have ventured further than a few kilometres beyond their release points.
One young kiwi had established a territory just a few hundred metres from where it was released six years previously. Another kiwi, which hatched from the first egg ever removed from the area in 2006, has paired up not far from his release site and is now producing his own offspring there.
Ms Ward-Smith said the Trust would be capturing kiwi for Operation Nest Egg on a neighbouring property many kilometres distant in the next 12 to 18 months.
“It will be exciting to see if any of these birds have microchips indicating where they were released.”
She said it had been interesting to plot known kiwi locations on the map and see how the available ‘territory space’ at Maungataniwha is filling up. This was what the Trust would expect to happen when kiwi are surviving and the population growing.
“There’s so much we can still learn about kiwi re-establishment in low density populations,” Ms Ward-Smith said. “One of the joys of our work in such extremely remote places as Maungataniwha is the ability to contribute in a useful way to the national discussion about the way they live, breed and disperse.”
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