November 28, 2020

I, Science

The science magazine of Imperial College

Meet the Kakapo. It is flightless, nocturnal, has whiskers, yes I am still talking about a bird. Also known as the owl parrot, the species is endemic to New Zealand.

It is such an odd contradiction of an animal. The Kakapo has large wings but cannot fly and yet it can be found feeding 20m up the nearest Rimu tree.  Sorry, I’m going to have to repeat that. It climbs twenty metres into the air using its beak and feet because it has lost the ability to fly. It is still a bird. The Kakapo has an excellent sense of smell to compliment its nocturnal lifestyle and has a powerful sweet aroma of its own; smelling (so I’ve heard) like musty apricots. Its feathers do not need the rigidity that is normally required for flying and so are extremely soft to the touch. It also genuinely does have whiskers called Vibrissae that it uses to navigate its way around the forest floor at night.

It is a predators dream. Large, relatively slow, easy to track by smell, it even comes out at night just to be extra amenable to mammalian carnivores. Worse still is a Kakapo in mating season. The males give out a booming low-frequency call that can be heard up to 5km away. They also boom for an average of eight hours a night, just in case any hungry animals missed them the first time round.

On top of this the Kakapo does everything slowly; it has an average life expectancy of 95 years and has to have a teenage phase before it is ready to breed. Females don’t start looking for mates until they are at least 6 years old, they don’t breed every year either. Instead they time their breeding seasons with the fruiting of particular tree species, such as the Rimu, that only bears fruits every two to four years. The result is one of the lowest rates of reproduction amongst birds.

How have they survived until now? Well, until humans arrived on the island, trouble really only came from the sky. They were only four raptor birds in New Zealand (only two species survive now) and all hunted in daylight. There was no need for the Kakapo to develop better defensive mechanisms than camouflage and staying absolutely still when disturbed. The arrival of humans and the introduction of cats, rats and stoats to the island changed everything.

By 1995, there were only 51 Kakapo left even though the birds were under one of the most closely monitored conservation schemes in the world. One of the greatest obstacles was that the birds were producing few female chicks. The mystery was solved when it was discovered that females can alter the sex of their offspring depending on food availability. They tend to have more males when there’s more food around because males are more energetically expensive to produce.

We still have much to learn about this unusual species but the breeding rate has picked up since this discovery. There are now 120 birds known to researchers and with two new projects creating safe habitats on nearby islands, things are looking up. Right now there is a new breeding season underway in the land of the Kakapo and last Friday came the best news of all, the first chick of the season hatched safely on Codfish Island. With another ten eggs ready and waiting the future may at last be beginning to look a little bit brighter for this extraordinary bird.