This is an extraordinary performance. He puffs out two enormous air sacs on either side of his chest, sinks his head down into them and starts to make what he feels are sexy grunting noises. These noises gradually descend in pitch, resonate in his two air sacs and reverberate through the night air, filling the valleys for miles around with the eerie sound of an immense heart beating in the night.
The booming noise is deep, very deep, just on. the threshold of what you can actually hear and what you can feel. This means that it carries for a very great distances, but that you can’t tell where it’s coming from. If you’re familiar with certain types of stereo set-up, you’ll know that you can get an additional speaker called a sub-woofer which carries only the bass frequencies and which you can, in theory, stick anywhere in the room, even behind the sofa. The principle is the same – you can’t tell where the bass sound is coming from.
The female kakapo can’t tell where the booming is coming from either, which is something of a shortcoming in a mating call. `Come and get me!’ `Where are you?? ‘Come and get me!’ ‘Where the hell are you?’ `Come and get me!’ `Look, do you want me to come or not?’ `Come and get me!’ ‘Oh, for heaven’s sake.’ `Come and get me!’ ‘Go and stuff yourself,’ is roughly how it would go in human terms.
As it happens the male has a wide variety of other noises it can make as well, but we don’t know what they’re all for. Well, I only know what I’m told, of course, but zoologists who’ve studied the bird for years say they don’t know what it’s all in aid of. The noises include a high frequency, metallic, nasal ‘ching’ noise, humming, bill-clicking, ‘scrarking’ (scrarking is simply what it sounds like – the bird goes ‘scrark’ a lot), `screech-crowing’, pig-like grunts and squeals, duck-like `warks’ and donkey-like braying. There are also the distress calls that the young make when they trip over something or fall out of trees, and these make up yet another wide range of long-drawn-out, vibrant, complaining croaks.
I’ve heard a tape of collected kakapo noises, and it’s almost impossible to believe that it all just comes from a bird, or indeed any kind of animal. Pink Floyd studio out-takes perhaps, but not a parrot.
Some of these other noises get heard in the later stages of courtship. The chinging for instance, which doesn’t carry so well, is very directional and can help any females that have been aroused by night after night of booming (it sometimes goes on for seven hours a night for up to three months) to find a mate. This doesn’t always work, though. Females in breeding condition have been known to turn up at completely unoccupied bowls, wait around for a while, and then go away again.
It’s not that they’re not willing. When they are in breeding condition, their sex drive is extremely strong. One female kakapo is known to have walked twenty miles in one night to visit a mate, and then walked back again in the morning. Unfortunately, however, the period during which the female is prepared to behave like this is rather short. As if things aren’t difficult enough already, the female can only come into breeding condition when a particular plant, the podocarp for instance, is bearing fruit. This only happens every two years. Until it does, the male can boom all he likes, it won’t do him any good. The kakapo’s pernickety dietary requirements are a whole other area of exasperating difficulty. It makes me tired just to think of them, so I think we’ll pass quickly over all that. Imagine being an airline steward trying to serve meals to a plane full of Moslems, Jews, vegetarians, vegans and diabetics when all you’ve got is turkey because it’s Christmas time, and that will give you the idea.
The males therefore get extremely overwrought sitting in their bowls making noises for months on end, waiting for their mates who are waiting for a particular type of tree to fruit. When one of the rangers who was working in an area where kakapos were booming happened to leave his hat on the ground, he came back later to find a kakapo attempting to ravish it. On another occasion the discovery of some ruffled possum fur in the mating area suggested that a kakapo had made another alarming mistake, an experience which is unlikely to have been satisfying to either party.