kiwi hatching New Zealand Conservation Trust New Zealand Conservation Trust
New Zealand Conservation Trust
New Zealand Conservation Trust

New Zealand Conservation Trust
Conservation Projects > Kiwi Breeding Program

Kiwi Breeding Program

Currently the New Zealand Conservation Trust is involved in breeding several species of kiwi. Our breeding program is run with the ongoing and invaluable support of Willowbank Wildlife Reserve and we operate the most successful captive kiwi breeding program in the world. 

Kiwi in New Zealand are undergoing a serious decline in numbers mostly due to the effects of predators. Currently in the wild 88% of kiwi chicks hatched in the North Island are killed within one hundred days of hatching. The most destructive predator of kiwi are stoats. It is estimated that they alone account for the deaths of 40% of the 88% mentioned earlier. It is estimated that the mortality rates are up to 95% for South Island species. These are alarming statistics for the continued survival of the bird which is our national icon. 

Our program starts with the breeding pairs of kiwi we hold at the reserve that enjoy a natural habitat environment with native trees and territorial areas for each pair. (For Operation Nest Egg a different process takes place) 

When an egg is laid the male kiwi sits on the egg. The egg is weighed and measured as soon as possible after being laid and this information is recorded and stays with the chick as part of its ongoing individual record. The male sits on the egg for half the incubation time of the egg and we have found hatching rates are more successful if this natural process is allowed to occur for this time. 
During this period the male looks after the processes of turning the egg and allowing for cooling periods when he is off the egg to feed. 

After 30 days the egg is lifted from the burrow, cleaned if necessary, to remove any potentially harmful bacteria and is placed in a carefully prepared incubator in the New Zealand Conservation Trust’s kiwi breeding facility. 

At this stage the egg is monitored as are temperature and humidity levels in the incubator. The egg is weighed and this detail, along with the condition of the egg and the date it was lifted from the nest is recorded. The egg is kept in a dark environment as they are thought to be light sensitive. The egg is weighed daily and these weights are also recorded. This process allows for tracking of the weight loss which is expected during the incubation of an egg. An egg is expected to lose between 12 – 16% of its weight during the incubation time. Regular timed cooling off periods are provided to emulate the processes of the male in the wild. 

Candling involves shining a special light through the air pocket at the end of the egg and this allows keepers to check on the chick inside the egg. During candling, which is done sparingly due to the light and heat sensitivity, the keeper is checking air cell enlargement, embryo development and the clarity and condition of the inner membrane and network of veins. These are all things which are good indicators of the health of the embryo. During the eggs time in the incubator it needs to be turned on a regular basis to mimic the actions of the male in the wild. This turning is done to prevent the chick inside from sticking to the internal egg membrane, and also allows the embryo to absorb nutrient from the egg albumen. This process of turning is done with a great deal of care to ensure the egg is never completely inverted. The egg is only turned in intervals of 45 or 90 degrees each time and follows a set pattern of turns. 

After a period of between 38 and 60 days in the incubator the chick hatches. The first stage of hatching for the kiwi chick is known as the ‘internal pip’ and involves the chick breaking through the membrane between itself and the air cell at the top of the egg. The next stage is the ‘external pip’ and this process can take up to 100 hours and often noises from the chick inside the egg can be heard during this time. The external pip involves the chick cracking the shell with their beak and enlarging this hole, also with the beak. The feet are used to help kick the shell free from their body. The process of external pipping can be a slow and delicate procedure. 

At this stage of hatching intervention is occasionally necessary if the chick is having difficulties and is generally given after the 100 hour period. Any intervention at this stage is very carefully and gently undertaken by experienced staff as this is a critical stage for the baby chick. 

After hatching the new chick is weighed and this information recorded. The new kiwi will also have its umbilical cord disinfected with manuka honey at this stage. 

The next step for the kiwi chick is to be placed into a special unit known as the TLC (thermal life support cabinet). This is where the chick will spend the next two/three days under close supervision and care from keepers. This TLC unit helps the chick to dry out and provides a closely monitored and balanced environment. During this time the chick is sustained by the yolk sac which is contained within the bird. This yolk sac nourishes the chick for up to two weeks. It is normal for the bird to lose weight during the first two weeks where after it can potentially take a further two weeks to reach its hatching weight. 

After 3 days the chick is big enough to be moved into a brooder pen. This pen has a deep floor covering of peat, a burrow and the other necessities such as water, worms and small stones for the birds gizzard. First the first week an incubator lid which has a special element in it is placed inside the burrow to keep the chick at the right temperature. As the chick grows older the temperature in this incubator lid is gradually lowered until it is in line with the room temperature. An ambient room temperature of 20 degrees is ideal at this stage. In this brooder pen the chick will start to receive a specially formulated diet which is weighed so as to allow us to track how much food the kiwi is eating. The bird is weighed daily for two months, then less regularly after this. 

Once the chick has reached an appropriate weight they are placed in a special area known as a pre-release pen. These pens have a burrow indoors for the bird but also have an outdoor area to allow for natural feeding habits such as probing to take place. During this time the amount of food the kiwi eats is recorded daily and the bird’s weight is checked on a weekly basis. These pre-release pens are a ‘hardening off’ area before potential release into the wild. 

When the chick has reached 1200grams in weight it is placed into our nocturnal house at which stage a decision is made in consultation with the Kiwi Recovery Program as to the future of the bird. It may be kept as a display bird in various institutions throughout New Zealand, may become part of captive breeding programmes or may be released back into the wild as it has reached a size which enables it to fight off predators such as stoats. The New Zealand Conservation Trust kiwi are found in 11 of the 13 holding institutions in New Zealand. 

All kiwi under our management are checked daily for general good health, the amount of food they eat is monitored and they are weighed monthly so as to keep an eye on their health and general condition. An increase in weight is a good indicator of a female kiwi carrying an egg which means that the cycle begins again allowing us to add another kiwi to our ever decreasing numbers of this species.

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