More about kokako

The first wild kokako chick at Pukaha Mount bruce is checked by doC staff.

Kokako were once common in forested areas throughout the North Island. Since human arrival their range has been contracting and their numbers dropping. This has been especially evident during the last part of the 20th century. The last reported sighting of kokako at Pukaha Mount Bruce was a note from Elwyn Welch that birds were seen in "an area of scrub adjoining Pukaha Mount Bruce " in 1949. This was one of the last sightings in the region.

The Kokako Recovery Group has had marked success in managing remnant populations and is now looking at extending the range of kokako, by releasing birds to establish this species in areas from which it has become extinct. Pukaha Mount Bruce is one of the favoured release sites. In the words of kokako scientist John Innes "there is no better place (for this work) in the North Island." Given that one of the last sightings in the region was at Pukaha Mount Bruce , that the health of the forest has improved markedly in the intervening 50 years, and that another species (kaka), living in the forest at that time has successfully established following release, there can be little doubt that the forest could support kokako.

In addition, the key predators of kokako are well known, as are the levels to which they must be controlled for successful kokako breeding and the optimum timing of control operations. Work at Pukaha Mount Bruce aimed at the reintroduction of kokako has the benefit of knowledge of the species gained over a number of years and the operation of a successful management regime for the species at its remaining mainland strongholds.

As with kaka, control of predatory mammals becomes critical at breeding time.

Kokako from a relict Taranaki population are currently held in the National Wildlife Centre aviaries. These birds were brought into captivity because there was no hope of sustaining the wild population. The Department of Conservation has made a commitment to return the descendants of these birds to Taranaki, should they breed in sufficient numbers. A similar strategy is proposed for a remnant on Mt. Moehau, in the Coromandel. Known release and reintroduction techniques would be of great assistance in meeting this commitment.

Birds were transferred from Mangatutu to Pukaha Mount Bruce for two purposes:

Experience with kokako populations that have fallen to very low levels and have subsequently recovered indicates that 5 pairs is a base from which a viable population can be formed provided targeted predator control is in place. This transfer follows the reintroduction of North Island kaka (Nestor meridionalis) to the Pukaha Mount Bruce forest by a combination of captive breed and release and soft release methods and is one of a number of reintroductions envisaged to return species to the Pukaha Mount Bruce forest as part of the Pukaha project.

Kokako release
The Kokako Recovery Plan has a long term goal of restoring the national population to ca 1,000 pairs by the year 2020, in sustainable communities throughout the North Island. They recommend that that management for kokako occur at 23 key sites, stating that this is a necessary minimum. The plan identified the Pukaha Mount Bruce forest as one of these sites and suggested a release in 2002. In order to support a breeding population of kokako key pest indices of <2% residual trap catch for possums and <2% tracking tunnel for ship rats are regarded as desirable, even though indices of <5% for both species can allow kokako to breed.

This level of uncertainty would change greatly if artificial incubation and hand rearing become proven techniques for raising the birds. in this case larger groups may be released.

Pest control in the early stages of the operation means that the birds have the best chance of establishing, without being targets to predators in the confused time immediately following the release. It also means that the forest itself is in as good a condition as possible to receive them, that the plant food sources are healthy and the birds can stay as healthy as possible while they establish their territories. The intensive monitoring required for the six non-territorial kokako was made possible only with radio telemetry. Without telemetry it would have been virtually impossible to find the six birds amongst the 1,000 ha of forest. There was the occasional brief sighting by other staff either in the forest or later on around the aviaries of the National Wildlife Centre. Even with radio telemetry equipment it was often difficult to sight the birds as they tended to move around a lot and were not very vocal.

Movements of the individual birds that made up the first transfer are as follows:

Whakatere - This was the only male in the first release. Whakatere was sighted a couple of times soon after release and then once on the public track between Bruce Hill and the end of the Hotel access track on the August 4 2003. He appeared to settle at one site early, spending a large amount of time in the area northwest of Bruce's Hill when other birds appeared to be still moving around. He may have moved around a bit more after the release of Turk, the second male, six weeks later, possibly even being displaced from Bruces Hill by the physically larger Turk. When Whakatere was away from Bruces Hill he was usually on the Billy Goat ridge and on the odd occasion around the northern end of the Echo track or on the Wildlife Ridge. He has spent a lot of time with Rain, though tracking and observation has shown no signs of breeding or courting. Rain and Whakatere were in the same general area from October until the end of monitoring in February. It is possible they have, or will, establish a territory at this site. A more definite picture will be known during the 2004-05 breeding season.

Rain - This female still had lilac colouring on her wattles when captured, suggesting that she was not fully mature when captured (although there are reports of adult kokako with pink wattles). Rain has tended to move around a lot, often near other birds. She was sighted in July soon after release on three occasions and in October was sighted around the aviaries of the National Wildlife Centre. Most of the time spent with any other birds was with Whakatere and she has been in his general area from October until the end of monitoring in February 2004. Although she was sighted many times around the aviaries in November and December and seemed to divide her time between there and Whakatere's area. During January and February she was only rarely observed around the aviaries. It is possible that Whakatere and Rain have paired but not bred. Further sightings of these two and close monitoring over the next breeding season will give a clearer picture.

Petal - This was one of the two presumed mature females captured for the translocation. Although she did appear to move around a lot, it was often from similar directions that her signals were received. The areas tended to be around the Billy Goat ridge, around the northern end of the Hotel ridge and on the eastern side of the Echo ridge up into the Braddick's block (appendix 3). Some of the triangulations put her in a similar area to other birds notably Turk and Pumpkin. Pumpkin was caught at the same site as Petal at Mangatutu as Petal, so they may be related, or at least known to each other. Turk spent time with her in the Echo ridge area. On the 18th of December 2003 Petal's remains were found among scented fern (Paesia scaberula) and grass on farmland adjacent to the Reserve. This followed repeated signals from the same area on the eastern side of Hotel Ridge. Cause of death was not immediately obvious as there were very few remains left: the transmitter, some feathers and the ends of the wings from the wrists. Remains of other birds, rabbit and a regurgitated pellet were also found. Analysis of these and photos of the site sugest the likely culprit is an Australasian harrier (Circus approximans).

Pumpkin - This was another female with slight juvenile colouring on her wattles (although there are reports of adult kokako with pink wattles). There were problems with the transmitter for this bird throughout the monitoring period. Very few signals were received for this bird compared to the others. Some long searches were carried out that should have left very little of the reserve uncovered without picking up the bird's transmitter signal. The bird did not appear to have much contact with other birds early on in the monitoring apart from the occasional encounter with Petal (appendix 4). During October, November and December there were more sightings and signals from around the aviaries, and sometimes Pumpkin was sighted with Rain., By January no further signals had been received so extensive searches were made. By chance, a signal was picked up from the road near the northern end of the reserve. The signal was tracked to a 50ha area of privately owned forest remnant that borders the north-western corner of the reserve, in a gully running away from the reserve. This may explains why the bird was never picked up when extensive searching was carried out as the terrain effectively blocked reception over a wide area. The bird may have started using this area relatively soon after release. When the signal was tracked the transmitter was found with the harness weak link broken and it was assumed that the transmitter fell off the bird. This was on the 27th of January, 2004, close to the estimated time of failure expected in the weak link built into the harness.

Gale - This bird was a presumed mature female when caught and following Petal's death in late 2003 though to be the only mature female at Pukaha. There was no early pattern to this bird's movements and she appeared to roam randomly throughout the reserve. She was sighted soon after release and was tracked on a couple of occasions but with no sightings. She was later tracked with Turk without sighting. On October 21 2003 both birds were sighted together in Highway block and were followed for about an hour. This sighting in mid October, along with the interpretation of previous tracking, suggested that they were a pair. See below for information on the establishment of a territory and nesting

Turk - This was the second male, the last bird released and the largest (deleted a bit here). His behaviour immediately after release also differed. Other birds that were released tended to hang around the ridge above the National Wildlife Centre for a couple of days at least. Turk, however, left almost immediately. Soon after release he triangulated to the Public Track / Hotel access junction. He spent a lot of time with Petal down the Echo ridge area early on but later spent more time with Gale . He was possibly sighted by a member of the Pukaha team and later by a DoC hunter east of Echo ridge. He was tracked a couple of times with Gale without sighting but on October 21st 2003 both birds were sighted together in Highway Block and were followed for about an hour. This sighting, along with the interpretation of previous tracking, suggested that they were a pair.

Establishment of Turk and Gale as a breeding pair
After being sighted together in the highway block on 21 October 2003 these birds predominantly triangulated to the same general location but they were occasionally with other birds. Through December their signals generally originated from the southern around to the eastern side of Bruce's Hill, usually at high elevations. On December 16 2003 both birds were down to within the Bruce Hill area, and Turk was observed feeding Gale. The behaviour prompted another sighting attempt as soon as possible and on December 19 2003 Gale was discovered sitting on a nest near the summit of Bruce's Hill. The nest was monitored through incubation and rearing and two chicks were banded on January 22 2004. Chicks began leaving the nest around February 3 2004 and were first seen fully fledged on the February 13 2004. Fledglings have been seen around the territory since being fed by both parents and possibly also by Rain. In April 2004 both chicks were seen at the National Wildlife Centre aviaries