Andrew Digby/New Zealand Dept of Conservation

The kakapo is a remarkable bird. The large parrot has lived in New Zealand for millions of years, and is evolutionarily unique. It has no close living relatives, is world's the only nocturnal flightless parrot, and scientists believe it can live for up to 90 years.The birds also have extremely unusual mating habits : The males inflate like balloons and emit a repetitive “heartbeat-like” sound (known as “ booms ”) in an effort to attract a mate, and the females only become interested in mating when a particular native tree, called the rimu, bears fruit -- something that happens every two to four years “They’re just weird and wacky . They’re extremely different from any other bird,” Digby, a science adviser at New Zealand’s Department of Conservation, told The Huffington Post. “If we lose them, we’d be left with nothing even similar.”Losing the kakapo almost became a reality a few decades ago. Kakapo populations plummeted to nearly zero in the 1970s, due to humans hunting them and introducing new predators including dogs and cats.“Kakapo used to be extremely common in New Zealand. They used to be absolutely everywhere,” Digby said. “European explorers used to describe shaking trees and kakapo just falling out of them.” (The bird may not be very good at flying, but tree-climbing is one of its noted skills.)When conservationists surveyed for the bird in the late 1970s, they only found a handful of them, and all of them were males. The bird was assumed to be functionally extinct.But then in 1980, researchers made an extraordinary discovery: four females on an island off the southern coast of New Zealand. The birds were promptly relocated to a special pest- and predator-free island , and the government initiated several measures to protect the parrots. In 1990, the New Zealand Department of Conservation established the Kakapo Recovery Group and launched an intensive program to monitor the birds 24/7. Chicks were hand-reared, and researchers undertook extensive study of the kakapo and its behavior.“It’s been a big, big effort,” Digby said.The kakapo is now on the road to recovery . Today, 154 birds live on three predator-free islands and in sanctuaries that are devoid of non-native mammals, insects and plants. A successful 2016 breeding season yielded a more than 20 percent increase in the kakapo population.Digby credits the New Zealand government’s commitment to conservation as a major factor in the bird’s recovery. “In conservation, there’s always a battle for funding," he said. "But we’re lucky that there’s quite a lot of emphasis here. The government support has been incredible."The Kakapo Recovery Group hopes that two of the three populations of kakapo, which are still considered critically endangered, will be self-sustaining in a few years. The ultimate goal, the group says, is to get the parrot back onto the mainland.“We once thought it was a crazy idea,” Digby said. “But the New Zealand government has been talking about making the mainland predator-free by 2050. It could really happen.”