The kakapo (Strigops habroptilus) is a curious creature. It’s chubby, flightless, and nocturnal. It’s the heaviest parrot in the world. It smells like flowers and honey. And, sadly, it’s really, really endangered.

Only 125 kakapos remain in the wild, living on a few small islands off the coast of New Zealand. The birds live under the close supervision of teams of conservationists who have tried for decades to help the kakapos replenish their ranks. Their efforts have met with mixed success, leaving the scientists to watch helplessly as these strange and charming birds fade away. 

But there is still hope for the kakapo. One researcher thinks she may have found an answer: vitamins.

The solution is nested within the problem. The kakapo’s food of choice during breeding season is the berry of the rimu tree (Dacrydium cupressinum). In good years, the rimu puts out fruit in abundance. But there have not been many good seasons lately; the trees have fruited only twice in the past 30 years.

Scientists have attempted to fill the gaps in the birds’ diets with specially formulated food pellets. The kakapos seemed to like a catered meal, but they wouldn’t breed after eating it. Some essential element was missing.

Previous tests of the kakapos’ blood revealed that they were calcium deficient, but even calcium-enriched bird food didn’t do the trick.

The solution may be simple, says Massey University nutrition scientist Pamela von Hurst. The birds just need more vitamin D.

Von Hurst and her colleagues performed a two-pronged test. First, they analyzed the rimu berries. They found that the berries contain high levels of both calcium and vitamin D. Then the researchers tested the kakapos’ blood. Sure enough, the parrots were vitamin-D deficient.

Vitamin D is essential for many bodily processes. Perhaps most importantly for the kakapo, it helps the body absorb calcium. Without calcium, the kakapo can’t support their heavy bones or lay viable eggs. But with it, they might stand a chance.

Von Hurst published her findings this week in the Journal of Steroid Biochemistry and Molecular Biology.

The kakapo conservation teams intend to add vitamin D to new formulations of supplemental feed. This year is also promising for rimu berries, Kevin Hackwell of New Zealand’s Royal Forest and Bird Protection Society told New Scientist. “We may get as many as 25 chicks if all goes well.” 

[h/t New Scientist]