It is an exceptionally fat bird (a good-sized adult weighs roughly two or three kilograms) and its wings are just about good enough to waggle about a bit if it thinks it’s going to trip over. But flying is completely out of the question.

Strangely, not only has it forgotten how to fly, it also seems to have forgotten that it has forgotten how to fly. Legend has it that a seriously worried kakapo will sometimes run up a tree and jump out of it, whereupon it flies like a brick and lands in a graceless heap on the ground.

It may also be the longest-lived bird in the world, with a suspected life expectancy of about 90 years. None of the kakapos known to scientists have yet died of old age and the chances are that some of the youngsters will out-live the people who are studying them. Perhaps this is because they seem to do everything more slowly than other birds: they are the Amazonian manatees of the bird world.

They also have an extraordinary mating ritual. When the breeding season looms, the male kakapo heads for the hills. He climbs higher and higher, on his short legs and big feet, and then digs a shallow pit – known as a ‘bowl’ -next to a rock face or tree trunk. He is looking for good acoustics: the bowl acts as an amplifier and the rock or trunk reflects his mating call across the wild valleys below.

Then he puffs up an enormous air sac in his chest, lowers his head, and starts to make a sound worthy of a Pink Floyd studio out-take. It’s rather like a heartbeat: a deep, powerful throb that is just on the threshold of what you can actually hear and what you can feel. This means that it carries for a great distance (more than five kilometres with the help of the wind) but you can’t tell exactly where it’s coming from – something, one might imagine, of a shortcoming in a mating call.

Once, before New Zealand was inhabited by humans, kakapos were exceptionally common birds across the country. But Maori settlers hunted them for food and for their skins and feathers. Then Europeans arrived and cleared vast tracts of land for farming. They also brought mammalian predators with them – everything from rats and cats to dogs and stoats – that promptly started to eat the hapless birds. The trusting kakapos didn’t know about predators (they had never learnt to worry about them) and made easy prey. Sitting ducks, one might say, or parrots.

So first there were hundreds of thousands of kakapos. Then there were thousands, then hundreds. Then there were just 40… and counting. The old night parrot of New Zealand was in serious trouble.