16 Apr 2019

Longest kākāpō breeding season

From Kākāpō Files, 12:00 pm on 16 April 2019

The number of living kākāpō chicks has risen to 75, with the final three due to hatch this week.

The oldest chicks are already beginning to leave their nests at night although they are still returning to sleep there during the day.

Daryl Eason, from the Department of Conservation’s Kākāpō Recovery team, says that the sex ratio of the first 49 chicks to be tested is 22 females and 27 males.

Female kākāpō Queenie with chicks Boomer-3-A-19, Alice-2-A-19 and Tumeke-2-A-19.

Female kākāpō Queenie with chicks Boomer-3-A-19, Alice-2-A-19 and Tumeke-2-A-19. Photo: Andrew Digby / DOC

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The technique for determining the gender of kākāpō, using either a small blood sample or tiny amounts of membrane left in the eggshell after hatching, was developed by Associate Professor Bruce Robertson at the University of Otago.

This season, a genomics team at Agresearch is carrying out the DNA analyses to determine both gender and paternity of all the chicks. Jeanne Jacobs says the team is currently determining the paternity of the chicks, which will prove whether any of the artificial insemination attempts have been successful. The scientists will also determine the gender of the remaining chicks.

As well as analysing living chicks, sex and paternity is also determined for dead chicks and failed fertile eggs.

The long breeding season

The first chick of the 2019 breeding season hatched on 30 January, and with the final one due to hatch this Friday 19 April, this breeding season will hold the records for both the earliest start and latest end to a breeding season.

Scientist Andrew Digby says the extended breeding season is the result of a large number of females renesting.

The total number of chicks hatched so far in this year’s bumper kākāpō breeding season is 83, and if three eggs due to hatch this week are successful it will bring the total number of chicks for this breedign season to 86. The remaining eggs were laid by Stella, who was the last female to mate.

There have been 8 chick deaths. The most recent chick death is Pura-3-A, who died suddenly. Cause of death is still being determined, but appears to be liver failure.

Two of the chicks in Hoki’s nest have been moved to other nests after their growth rates slowed down. Hoki herself now weighs less than a kilogram, while her three chicks together weighed four kilograms, and Daryl Eason says she was probably just struggling to feed them. The kākāpō team will be giving her a health check and hope that she will be able to cope with her one remaining foster chick.

Leaving home

The first wild kākāpō chicks on Anchor Island are beginning to explore away from the nest at night, although they return during the day to sleep.

Daryl Eason says that the terrain on Anchor island is very steep, and to prevent clumsy chicks rolling down a hill and being unable to get back to the nest, the kākāpō team will be building small fences below some of the nests. He says the rainfall on Anchor Island is high and it is important that chicks can return to the nest to find dry shelter.

Andrew Digby says the remaining seven hand-reared chicks currently in Invercargill will begin moving to a weaning pen on Whenua Hou later this week. The chicks have already begun ‘rain training’, where they are sprayed lightly with water and encouraged to take shelter, to help them acclimatise to the outside world.

Medical emergencies

Chick Esperance-1-B is at the Dunedin Wildlife Hospital, and has had a CAT scan to investigate a small blister-like bulge on the chick’s head. The scan showed that the skull’s sutures have not joined properly and the ‘blister’ is actually part of the chick’s brain.

Daryl Eason says Esperance-1-B is doing very well despite the brain bulge, and the veterinary team is considering whether to operate now or later, when the chick is bigger.

Esperance-2-B had to be treated for a respiratory infection but has now been returned to a wild nest.

Founder male Arab, one of the original Stewart Island males, is being treated at Auckland Zoo for facial injuries sustained during a fight with another male. Arab already sports a damaged eye from a major fight about 20 years ago on Hauturu, and the vet team are deciding whether to attempt to repair that eye’s damaged eyelid or to remove the eye altogether.

Find out more

If you would like to know more about kākāpō you can follow the Kākāpō Recovery Programme on Facebook and Instagram. Kākāpō scientist Andrew Digby and Kākāpō Files producer Alison Ballance are on Twitter.

Find the full kākāpō story in the book Kākāpō – rescued from the brink of extinction by Alison Ballance (2018).

UPDATE 18 April

The chick Stella-1-B hatched on 15 April. and chick Bella-1-A died on 18 April, keeping total number of living chicks at 75.

Hoki has been rushed to Auckland Zoo for urgent veterinary treatment, following concerning blood test results.

UPDATE 20 APRIL

The chicks Stella-2-B and Stella-3-B have hatched, bringing the number of living chicks to 77 out of 86 hatched.

Solstice has been found incubating her third clutch of three eggs. Two are definitely infertile and the third is yet to be confirmed. This raises the total egg tally to 252.

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