Merton and his colleagues learned that the male kakapo, puffed up like a feathered balloon, sits inside his bowl, which serves as a small amphitheater, and sends out a pulsing, low-frequency call, known as booming, which sounds at first like someone blowing across the top of an empty milk bottle. As the calls continue, sometimes for as long as eight hours, the intensity increases until it resembles the blast of a foghorn: Ooooom! Ooooom! The long-wave hum can travel up to three miles.
In 1977, against all odds, Merton and four two-man teams came upon an estimated 200-strong population of kakapo on 670-square-mile Stewart Island, New Zealand’s third largest, about 100 miles south of Fiordland. Again, all were male. Merton despaired. Had every female kakapo been wiped out by some disease or predator? Was the species doomed? Not until 1980 did a tracking springer spaniel on Stewart Island pick up a kakapo scent and lead its handler to a smaller, more slender and greener bird. Merton examined it and declared that the search for a female was over. Four other female kakapos, along with their nests and chicks, were discovered in the vicinity soon after.
But Merton’s jubilation would prove short-lived. After the first female was banded and released on Stewart Island, she disappeared. Soon after, researchers began finding kakapo carcasses. Within two years, the known population of adult kakapos on the island decreased by nearly 70 percent, probably due to feral cats. Again, the bird hovered on the brink of extinction. A new policy was called for.
Over a decade starting in 1982, the 61 surviving Stewart Island kakapos were captured and transferred to Little Barrier, Maud and Codfish, three small, nearly predator-free island sanctuaries.
Then, in 1999, on maud island, merton discovered a nest containing three eggs. “We’ve waited more than 20 years for this nest,” he said to his team. “It must succeed!” The nest was perched on a slope so steep that researchers had to cut a winding staircase of 140 steps to reach it.