Kiwis in 'severe reproductive bottleneck'

TAGGED: Helen Taylor is using electronic tags to observe kiwis.
TAGGED: Helen Taylor is using electronic tags to observe kiwis.

Research into the effects of inbreeding on kiwi populations is showing the native bird is trying hard to reproduce, but it is too soon to tell whether inbreeding is having an effect on failure rates.

The little spotted kiwi is one of the rarest breeds, with only about 1600 in certain places throughout the country. Those 1600 all originated from just five Kapiti Island little spotted kiwi.

Victoria University PhD student Helen Taylor is using radio tags to monitor kiwi in Zealand and Long Island in the Queen Charlotte Sound. She said the research, which began more than a year ago, had already produced "interesting" results.

"What has been surprising is the amount of reproductive effort the birds were putting in."

She said it was common for kiwi to only lay one egg, but there had been increasing cases where the birds were laying two.

Taylor is investigating the effects of a "severe reproductive bottleneck" on the genetic makeup of the kiwi, but she said it was far too early to tell numbers of fail rates, or whether any failure rates could be attributed to inbreeding.

She has completed the first season of data, and is preparing for the second. The genetic data from the first will have to be analysed by Taylor in the United States in a few months time.

The birds in the study are fitted with radio tags about the size of the top part of a human thumb. They are programmed with "chick timer" software that monitor the birds' activity patterns and the incubation status of eggs.

Taylor only tracks males—once  a week in Zealandia and once every six weeks on Long Island—as in this species it’s the male who sits on the egg.

Chicks that hatched successfully were measured and weighed. In cases where the egg had failed to hatch, the egg is taken back to the lab for autopsy.

"We’re still in the early stages of understanding the population genetics of little spotted kiwi, but we do know that big reductions in population size often lead to reduced genetic diversity and increased incidence of inbreeding.

"My findings will tell us more about this species of kiwi but could also give us clues about the prospects for other animals with similar histories."

Ultimately, Taylor hopes to come up with a set of recommendations that will feed into the Department of Conservation’s Kiwi Recovery Programme.