Catching kiwi to take their eggs sounds like something a predator might do, not a conservationist.
But this counterintuitive technique is helping to keep the circle of life of one of the iconic birds going in Hawke’s Bay.
In early May, a group of keen kiwi conservationists met deep in the Maungataniwha Native Forest, in inland Hawke’s Bay, to find as many adult male North Island brown kiwi as they could.
To many New Zealanders who are used to seeing images of juvenile kiwi being released into the bush, the business of catching adult birds may seem a bit odd.
But catching these kiwi is vital, Forest Lifeforce Restoration Trust chairman Simon Hall says.
The eggs that are sent to captive facilities for incubation, and the resulting kiwi chicks that are nurtured until they are large enough to defend themselves from stoats and other kiwi-killers, need to come from somewhere.
That somewhere is the nest of breeding kiwi hidden deep in the remote, dark corners of damp, mossy forests.
The process of finding the eggs starts with catching adult males and fitting them with a small radio transmitter.
The birds are then released into the areas where they were caught, free to get on with their lives and breeding activities.
Once a bird is fitted with a transmitter, the signal will tell conservationists where its nest is and how many days the male has been incubating the eggs.
They can then wait for the bird to leave its nest to forage before carefully removing the egg at night for safekeeping.
The kiwi catchers target adult male birds rather than females or juveniles because with North Island brown kiwi, the adult males incubate the egg.
Hall said it was far better to take the egg and send it off for incubation and rearing than for it to be scavenged by a predator.
“It’s always nice to read stories or see footage of juvenile kiwi being released into the bush, to start their lives in the wild after having been reared in creches or protected areas,” Hall said.
“But in order for that to happen, full-grown birds need to be caught.”
Fully-fledged chicks released back into the forest after being reared in safety have about a 70% chance of survival, Hall said.
This contrasts starkly with the 5% chance kiwi have of making it to adulthood if hatched in the bush and left unprotected.
To find the birds, trained volunteers or specialist kiwi catch crews will listen out for the final calls a kiwi makes at night, usually shortly before sunrise. Once these positions have been triangulated, specially trained kiwi sniffer dogs will be sent in.
At this time, the scent of the kiwi lies heavy on the vegetation and the dogs are able to home in on the birds. Their training means that this is done with the least possible noise and disturbance.
The 13 kiwi caught in the Maungataniwha Native Forest in May bring the number of birds there fitted with transmitters in the area to 56.
These 56 birds comprise the pool of kiwi from which the Forest Lifeforce Restoration Trust collects upwards of 90 viable eggs each year for incubation at the National Kiwi Hatchery in Rotorua and The Gallagher Kiwi Burrow at Wairākei.
The resulting chicks are reared at the National Kiwi Hatchery, the Napier Kiwi Creche managed by Save the Kiwi, or at a new creche at Tāngoio, near Napier.
The trust first started contributing to Operation Nest Egg in 2006. It has now released more than 700 juvenile kiwi back into that forest or into other heavily pest-controlled areas to help re-establish viable populations.