Captive Rearing Of Takahe

Forest and Bird, Volume 17, Issue 4, 1 November 1986, Page 14

Captive Rearing Of Takahe

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Craig Robertson New Zealand

Wildlife Service

Fo the past ten years the New Zealand /. Wildlife Service has been researching and preparing an intensive management plan dedicated to the preservation of the endangered takahe. There are three parts to this plan: e To enhance and expand the existing wild population and re-establish further wild mainland populations. e Toestablish an additional population on a predator-free island. e To develop a captive rearing station. The third part of this plan is now fully operational at the Burwood Bush Takahe Rearing Unit, part of the Gorge Hill Scientific Reserve, a 1350 hectare area of red tussock and beech forest about 35 km east of Te Anau. One of the last remaining extensive areas of lowland red tussock, at present it is being managed jointly by the Wildlife Service and the Lands and Survey Department.

Significant increase

When the flightless takahe was rediscovered by Dr Geoffrey Orbell in the Murchison Mountains of Fiordland in 1948 the population stood at about 500 birds. By 1982 it had declined to an all-time low of 120 birds but now stands at approximately 180 wild birds — a significant 20 percent increase in numbers over the past two years. In the wild, takahe usually rear only one chick each breeding season, yet most pairs have a two egg clutch. Most nests will have two ‘good’ eggs (fertile and developing); in some both eggs will be infertile. Between 1982 and 1985 an egg manipulation programme was carried out, the aim being to ensure that each pair had a fertile egg. Eggs are ‘candled’ (shining a light through the shell) to determine the presence of an embryo. Fertile eggs were transferred to nests which had infertile eggs, and from each of fifteen nests one egg was re-

moved and taken to Burwood Bush to be artificially incubated. From 1986 no egg transfers will be made, but instead whole clutches from 10 pairs will be removed for artificial incubation. It is hoped that the pairs which have had eggs removed will relay. This has already proved successful with several pairs.

Artificial rearing

Captive rearing methods and research carried out on takahe at the National Wildlife Centre at Mt Bruce and the Te Anau Wildlife Park have helped develop the new technique. At present the National Wildlife Centre has six adult birds and this year, for the first time, twin chicks. Altogether eight takahe chicks have been reared to independence at Mt Bruce. The Wildlife Service first attempted artificial rearing of takahe (isolation technique), at the Te Anau Wildlife Park in a temporary

set-up over the 1982/83 breeding season. From four eggs, three chicks were successfully raised. These birds are now in Captivity at the park. In the 1983/84 season six chicks were raised and during 1984/85 three chicks. These nine takahe were transferred to Maud Island in the Marlborough Sounds in April '84 and June '85 as a trial for the establishment of takahe in a pasture grass/island situation. Permanent rearing facilities have now been built alongside State Highway 94 overlooking the Burwood Bush Reserve, and, in November 1985, 16 eggs were brought out in three transfers from the Murchison Mountains. Eggs brought out of the mountains are placed in incubators in an air-conditioned room. Once a day every egg is candled and accurately weighed. Hatching dates can then be calculated, based on the size of the egg and how much weight loss has occurred. As the incubation period of 28-30 days nears its end, it is amusing to watch the eggs rocking about and to hear the baby takahe cheeping away inside the shell. At this stage, taped brooding calls of a parent bird are played through a speaker in the incubator. Just before the chick breaks completely out of the shell it is removed from the incubator and placed under a fibreglass model surrogate parent in a specially de-

signed brooder. This is to prevent imprinting to humans when the chicks are very young and to imitate as near as possible the rearing conditions in the wild.

Landscaped floor

The ‘parent’ is fully insulated, has a built-in speaker through which brooding calls of the parent are played, and a pet warmer pad is used to keep the chicks warm. Each brooder has a fibreglass landscaped floor, a small pond and a pot-planted tussock. A

one-way glass observation window allows the staff to monitor the birds without themselves being seen by the birds. The brooders have been designed with two identical sides separated by a pulleyoperated sliding door so that the chicks can be moved into the other side to allow regular cleaning of each brooder. The artificial lighting is programmed to coincide with daylight hours, and helps to keep the brooders ata constant temperature. Each brooder houses up to four chicks of a simi-

lar age. It is important that there be as little age variation as possible since older chicks become dominant and attack the younger ones. Last season all 16 eggs hatched but one chick died minutes after hatching at the wrong end of the shell. Another chick died from unknown causes when only a few days old. A further chick died some weeks later after failing to gain any weight or strength.

Maternity annexe

The brooder room resembles a maternity annexe with hungry, noisy, cute little balls of black fluff quite unbalanced on their oversized pink feet. Feeding the chicks is a long and involved process. From 7 a.m. to 10 p.m. the chicks require food once every half-hour. The nutritious diet consists of tussock (Chionochloa pallens and C. rubra), clover, carrot, cabbage, potato, dog food and ‘Farex’ baby food. This is all finely chopped, mixed together and served in conjunction with a plateful of moths, all devoured in a matter of minutes. Puppets are used to feed the chicks — a blue material sleeve with red wooden beaks — while a small speaker held in the hand emits a deep guttural takahe feeding call. It can become frustrating trying to feed equal amounts to the little white-tipped beaks of squabbling baby takahe. Between feeds, many hours are spent preparing the food, including the tedious job of picking thousands of tussock tillers and stripping the base down to the juiciest inner core. During the first three weeks of feeding it is critical that the food does not contain coarse fibre as this may block the chick’s digestive tract and lead to death.

Strict hygiene

Visitors to Burwood may well wonder at the people who look like butchers in their white coats and white gumboots. Well, they are actually Wildlife Service staff and it’s all in the cause of strict hygiene. A foot bath before entering the building is also essential. These precautions are to prevent diseases from entering the reserve, such as erysipelas which comes from poultry and pigs, and avian tuberculosis. For this reason the reserve is closed to the general public. The chicks are allowed to move to outside pens at about six weeks of age. At this stage they are about half-grown. The outside pens have two metre-high solid fences surrounding them and birds are watched through one-way observation windows. They can support themselves by feeding on the tussock in the enclosures, although supplementary feeding is also necessary. The birds remain in these enclosures for four to six weeks. During the whole period, a person is required to live in the brooder building to keep an eye on everything. Perhaps the most interesting time was when the birds were released onto the reserve in March of this year. Ten hectares of the reserve have been fenced off with a pre-dator-proof barrier of wire mesh with three electric wires on outriggers at the top and two on the bottom. The wires are connected to a solar power unit which can dis-

charge 10,000 volts, and to a security alarm system. The area is also being intensively trapped for stoats, cats and possums but it appears from the few catches that predators are probably in low numbers.

Behave like wild takahe

The birds released have been watched periodically from hides constructed in the area, and they appear to have adapted well. They are finding their natural foods easily and are behaving just as most wild takahe do — curious but wary of humans. They react instinctively to falcons and hawks flying overhead. Efforts to prevent imprinting appear to have been successful. We will have to wait a further two years, when the birds will be of breeding age, before we know if the programme has been a total success.

It is hoped that by then half the total of semi-captive takahe will have been released into Fiordland’s Glaisnock Valley (in the Stuart Mountains just north of the Murchison Mountains.) This will establish a new population in the wild and thus act as a safety measure should the Murchison Mountain population, for any reason, fall. The remaining takahe reared at Burwood will form two separate semi-captive populations. It is envisaged that 800 hectares of the reserve set aside for takahe will eventually be completely predator-proof fenced. At present only small extensions take place each year due to the enormous cost. A bright future looks certain for the regal takahe, and perhaps other species later on, with the establishment of the Burwood Bush Takahe Rearing Unit and associated reserve area. Pa