A string of minor thefts may have gone unnoticed in Mount Malloy.
First to go missing was a beer-can ring-pull. Then it was a sliver of clear glass, then a bleached snail shell, more glass and then a pink plastic straw. Once the first pink straw disappeared a whole string of them followed, each, like the first one, new, fresh out of the packet. Someone lost a mauve felt-tipped pen, someone else a purple hair band, and to this day the victim whose small red cotton-stuffed heart (embroidered with “I Love You”) was stolen probably has no idea who the culprit is.
These items and more all turned up at one location. Each one had been deliberately and carefully selected, filched and flown away with in secret. Then, as carefully as they were stolen, they were meticulously deposited and arranged.
The lengths to which males will go to attract a mate are amazing. From the tiny winter wren’s immensely powerful song to the radiant fan of the peacock’s tail, from the aerial diving display of the snipe to the beak-flagging display of the Dalmatian pelican, in each case the male is intent not merely on attracting the attention of a female but on persuading her to participate in a shared genetic future. In some species, the males rely on patterning and gaudily colorful plumage; in others they sport extensions, pennants, racquets, frills or crests. In many species, song is crucial. In all species, showing the appropriate behavior at the correct time and in the right place, along with other visual cues, is needed to attract and persuade a female.
One group of birds, hailing from Australia and New Guinea, though not generally startling in their plumage, nevertheless succeed in exciting their females. The key to their success is their skill in exterior decoration. These are not fly-by-night cowboy decorator crews doing shoddy work. They invest enormous amounts of effort and time in their creations.
As in all decoration, the “ground-work” is crucial: picking the spot, planning and preparation. An open area, sufficient cover nearby with plenty of perches and sufficient, but not too much, sunlight reaching the spot, are all important. Males may compete over a choice spot long before they take any steps to entice a female. Once they have established a clear right to “the spot” they then set about building.
Grasses, shrubs and trees all supply the building materials — a twig here, a stem there. Each piece is laid carefully, some to make the flooring, others for the walls. Woven together using only the beak as a tool, the walls rise, dense and strong like a short section of a maze. Once the walls have reached the desired height, once the central portion of the bower is sufficiently flattened in the middle and appropriately curved up toward the walls, then the male begins his part-time job: light-fingered thievery.
|A cock bowerbird considers a knotty aesthetic problem.|
|Female bowerbirds judge prospective mates by the taste and artistry displayed in the bowers the males construct.|
A greater bowerbird is the culprit that has been spiriting tiny objects away from the residents of Mount Malloy in Queensland. A straw here, a piece of glass there, the hair band and of course that little stuffed heart. Early in the morning, he spends his time titivating his bower, adjusting a grass stem or two, moving a ring-pull or a piece of glass, but when a female passes by he shifts into full courting mode, taking short flights, jumping, hopping and prancing, dropping to the arena around his bower, picking up a prominent shell and ostentatiously adjusting its position, dropping it again quickly and then moving a straw.
His busy movements become even more intent as the female approaches his bower. He ducks and weaves, enters the bower, adjusts a piece of grass and drops a tiny piece of worn green glass so that it chinks against a small stone, all as if to say, “See, this is the way it should be, don’t you think that the stone should be just here, and the glass just there? Don’t you agree?”
Time and time again he repeats the process. Some females seem to like the location, but were not so enamored by his bower; others love the bower, but aren’t so sure about his decoration. Then at last the female he’s been waiting for arrives, his perfect soul-mate. She likes the spot, loves his bower and his decoration, but is shy — or is she just being coy and testing him, putting him through his display paces?
Either way, he is smitten.
She hesitates outside the bower, so he runs through it as if extolling all its virtues: the view, the decor, the way the sunlight struck it. At last she ventures to the entrance — but then shies away. He starts his courtship all over again, standing in front of the tunnel while she stands beyond it at the back, he toyed with straws and shells, working hard to draw her back toward the bower, enticing her into the far end of the tunnel of love. She is “the one,” but he’s going to have to work even harder to convince her. He moves up to the next stage of courtship.
The greater bowerbird’s sandy, somewhat drab brown plumage appears unrelieved by coloring; the courting male relies almost entirely on the colorful items that he can gather — but there is one exception. Suddenly he tips forward, bowing, turning his neck and fluffs the feathers along the sides of his head. As his crown feathers part he reveals a bright lilac patch on his nape.
Now he becomes seriously intent. He rushes to the front of the bower, picks up the purple hair band, runs to the entrance and alternates between bowing and displaying his lilac patch and dangling the promised hair band before her. When she doesn’t respond, he drops the hair band and runs round to the back of the bower where she is. There he picks up the little red heart embroidered with “I Love You” and proffers that before running back round to the front again and plying the hair-band and his own lilac nuchal crest.
At last she seems convinced. At last she enters his bower and lingers. The bride-to-be admires his decorative skills, but has her own minor adjustments to make. She primps and pokes, adjusts and replaces the tiny items in the bowl in the center of the bower, and then the ritual courtship concludes in an anticlimactic finale: They fly off together to consummate their bond elsewhere.
The bower’s purpose has been served; now the hard work of building a nest and rearing a brood will begin.