For some reason I don’t seem to write about parrots very often on this blog. I’ve only written about the Red and Green Macaw, and other than that have ignored this group of birds completely. I think it’s because parrots are, in my mind, domesticated birds. But there are many species of parrot in the wild, and today’s animal is one of those.
The kakapo originally ranged all over New Zealand, but today no longer survives there. The introduction of predators by European colonists wiped out all kakapos on the main islands. Today wild populations of kakapos only exist on three predator free islands: Codfish, Maud, and Little Barrier island.
Kakapos are flightless parrots, which is the main reason why they were such easy pickings for the introduced predators. They are very good climbers, however, and can jump from the tops of trees, using their small wings as ‘parachutes’. They make up for their flightlessness by being quite large — they are, in fact, the largest species of parrot. Kakapos can reach lengths of 64 cm, and weigh up to 4 kg. They are covered in yellow-green feathers that help them blend into local vegetation.
Kakapos are different from other parrots in many ways. For one thing, kakapos are nocturnal. They have a few adaptations to help them make their way around in the dark. First, kakapos have a bunch of small feathers that surround its beak, acting as whiskers so the kakapos can find their way around the forest floor. They also have an excellent sense of smell, another unusual trait for a parrot.
The breeding system in kakapos is also very unusual, and it is the only flightless bird in the world to use a lek breeding system. Male kakapos gather on hills and ridges, fighting with one another for the best spots. Once a male has secured his display spot, he will dig depressions into the ground at different locations on the hill. These bowls help amplify the males’ mating calls, which can be heard up to five kilometres away, if the wind is right. Male kakapos are meticulous about keeping their bowls clean, and will call from different bowls to send their calls in as many directions as possible. It sounds like a lot of hard work, and it is. Males call for about eight hours a night, for a duration of three or four months. They can lose up to half their body weight from the strain.
A female kakapo lays one to two eggs, on the ground under cover or in hollows. She incubates them for a month, but must get up and feed during the night, leaving the scrumptious eggs vulnerable to cold and predation. If the chicks make it to hatching, the female will feed them until they are three months old, at which point the chicks fledge and start to gain some independence. They continue to hang around their mother until about six months of age, at which point they leave for good.
Kakapos are teetering on the edge of extinction — today only 126 kakapos exist in the wild. Thanks to human introduced mammalian predators, these birds were nearly completely wiped out. Extensive conservation efforts mean they are still around, but keeping the species going has been extremely difficult.
There are a number of reasons for this, one being that mammals are quite tenacious, and keep colonizing islands set aside for kakapo habitats. Another is the breeding habits of kakapos; these birds have and extremely long lifespan (an average of 95 years and a maximum of 120!!), and thus do not breed every year. In fact, kakapos only breed in years when fruit trees produce an abundance of food, which occurs every three to five years.
Conservationists were able to increase kakapos’ breeding rates by providing them with supplementary food, but ran into problems with this strategy. You see, female kakapos are able to control the sex of their eggs, giving birth to more males (which are larger) when fed a protein rich diet. For conservation purposes, female birds are much more valuable than males, and so scientists have to give the birds enough food to induce a breeding season, but not enough so that most of the chicks are male. They’re starting to get the formula right, and the kakapo population has been increasing steadily (albeit slowly) for the last few years. Hopefully this trend will continue!