09/03/2011
Fertility rates of kakapo on Codfish Island are growing as dud males are weeded out of the breeding mix.
Department of Conservation Southern Islands area manager Andy Roberts said 20 eggs had been laid on Codfish, west of Stewart Island, this year and of those 15 were fertile, about 25 per cent more than eight years ago.
The figures follow the birth of three kakapo chicks on Codfish Island in the past week, which has increased the endangered species population to 123.
DOC is still waiting for eight eggs to hatch, while a further four embryos have died.
However, the increase in fertility was great news for the kakapo recovery programme and while it was unknown what caused it, scientists believed it was the result of removing dud males, help from artificial insemination and increased bird numbers, Mr Roberts said.
Males that did not perform well were basically "put out to pasture" on another island and the increased competition between the growing population on codfish seemed to help fertility rates, he said.
"You have your duds and your studs, and your duds are usually put on other islands. It is like a stud farm operation I suppose, but it just takes a while (for the breeding season) to come around again," he said.
Kakapo breeding coincided with the fruiting of rimu trees about every three years, but the amount of eggs this year was less than the last season because of a lack of fruit believed to be caused by the large snow fall in September, he said.
DOC kakapo ranger Jo Ledington was disappointed the snowstorm destroyed much of the fruit seed, but said the three new chicks were doing well.
"Nothing is easy when you're dealing with such a small population, but it'll be fantastic to have a few more chicks running around," she said.
No more eggs will be laid this season and the amount of chicks born should be known by the end of the month.
