Calcium vital for survival of kakapo

Kakapos' finicky breeding habits have been linked to calcium found in rimu tree fruit during heavy fruit periods

Researchers hope a dose of calcium will help spice up the sex lives of the endangered kakapo.

The rare birds' survival chances have not been helped by their finicky mating habits, which are linked to their favourite food, the fruit of the rimu tree.

Kakapo only breed when rimu trees fruit heavily - a phenomenon called "masting" that happens every three to five years.

Massey University nutritional ecologist David Raubenheimer has been working on a project to find the best way of boosting the kakapo diet during lean years.

He developed a mathematical tool to compare the nutrients needed by kakapo to nutrients in their food.

Till now, conservationists have fed protein-enriched supplements to kakapo, as protein is a key nutrient for breeding in many species.

But Professor Raubenheimer has found what kakapo really needed on their menu was calcium.

"Calcium is needed in high levels during breeding, for the development of egg shells and for bone growth. It's also significant that kakapo have an unusually large skeleton, and hence a high demand for calcium," he told Massey News.Rimu fruit contains lots of calcium, which could be why kakapo only breed during "mast years".

Researchers will test the calcium theory as soon as February if the next rimu fruit season fails.

LUSTY BOOMERS

Kakapo (night parrot) are among the rarest birds in the world - just 92 are left.

Male kakapo "boom" deep messages of love like feathered Barry Whites, but with extra stamina - a lusty bird can make the noise up to 17,000 times a night.

Kakapo live on two predator-free islands - Codfish Island, near Stewart Island, and Anchor Island, in Dusky Sound, Fiordland.

This year has been good for kakapo, with seven chicks hatching on Codfish Island.