Meet the Bird That Lies and Tricks Its Way Into Sex

Disneyland’s a lie. Mickey Mouse, for instance, isn’t a mouse at all, but a costume with a person inside. The architecture, too, is deceptive. That giant castle isn’t as tall as it looks, because designers deployed something called forced perspective, making the windows near the top smaller so they seem farther away.

It’s some next-level sneakiness that the great bowerbird would find laughable. It was deploying its own visual tricks long before Walt Disney came around. The male great bowerbird constructs a beautiful tubular structure out of twigs, depositing bones and snail shells to make courts at either end. He arranges these in a very specific way, though, opposite of what’s going on in Disneyland: By deploying forced perspective, the male bowerbird actually makes his court look smaller. Also very unlike Disneyland, he does it to help him get laid.

This is the saga of bowerbird hanky-panky, a romance packed with more lies, illusions, and thievery than a soap opera—with none of the insufferable soft focus.

In Australia and New Guinea, 24 species of bowerbird undertake some of the most bizarre mating rituals among avians. Some males build big cave-like structures—known as bowers—out of sticks, clearing a court in front where they hoard objects of very particular colors. A pile of blue junk, for instance, might include berries and the odd piece of blue plastic. Other bowerbirds build simpler, smaller “avenue” bowers—two rows of sticks arranged vertically to create a kind of tunnel.

The male great bowerbird is in this latter camp. Among the builders, his bower is kind of meh if I’m being honest: He chooses drab rocks and snail shells and bones to decorate his court.

The female bowerbird doesn’t really care, though. Here’s how the seduction goes down. The male flutters into a bush above his bower and calls to the female. Should she join him, he’ll drop down to his crib and take up position in one of the courts. “He starts strutting about and then she goes inside [the bower], and he struts about a bit more and makes a funny sound,” says evolutionary ecologist John Endler of Australia’s Deakin University. “It’s sort of like, tick tick tick tick.”

Now pretend you’re a female great bowerbird. The tight walls of the structure direct your attention to the court. If the male had placed objects of any size willy-nilly throughout the court, to your eye the court would seem fairly large: Objects farther away of course look smaller and give a sense of depth.

Notice the arrangement of larger objects farther away from the bower. This tricks the female into thinking that the court is smaller or, at the very least, that she’s on acid.

But that’s not what you see here. The bones and stones and such all look to be the same size because the male is tricking you. He’s placed the larger objects farther away from your eye and the smaller ones closer to you. “The effect of that is to make a more even pattern,” says Endler. “It would probably have an effect of making the court look smaller and therefore the bird itself might look larger.” He’s using the art of forced perspective to show off.

That’s not the only visual illusion the bowerbird uses. In another part of the mating process, he takes up a position off to the side of the bower entrance, popping just his head into view to wave objects at the female, real needy-like. The males who find the best, most colorful objects are the most desirable, after all.

Here’s where it gets interesting: While the outside of the bower looks fairly plain, the male has painted the inside red by chewing up bits of plants and fruits. He didn’t do that to get the female in the mood—he’s actually messing with her color vision. The male picks up a typically colorful object, which she sees set against the dullness of the court, and gives it a wave. He throws the object away, grabs a new one, and gives that a wave. He’ll also flash the vivid crest on the back of his head every so often for good measure.

All the while the female’s eyes are adjusting to the red paint lining the bower. As this is happening, her retina is comparing the data from its red-sensitive cones and green-sensitive cones in order to sense colors.

But the paint is overwhelming the red cones. “The effect on the bowerbird is she’s going to become less sensitive to red light, which means that green objects are going to be brighter,” Endler says. The battle between red cones and green cones has tipped toward the greens. (Human peepers work the same: You can see how tightly green and red are paired in your eyeball with this demo. By staring at green stripes, you desensitize your green cones, so when you look at something white, red magically replaces the green.) Indeed, the male will wave a disproportionate amount of green objects to red ones in order to impress her.

The male great bowerbird’s beautiful crest is as alluring to female bowerbirds as the human male’s fedora is to women. Wait…

After an average of a minute or so of all this, the male will run around the back. If the female is receptive, she’ll let him mate with her. If not, she’ll just burn him and fly away.

Males don’t only have to worry about how to best seduce the ladies. Opportunistic males will often tear down their neighbors’ bowers or steal objects left unattended. This is relatively rare if bowers are nice and spaced out, perhaps over a half mile apart, but as density increases, so does the marauding. “There’s the other side of the story: If you’re going away to maraud someone, your own bower might get ruined,” Endler says. “Sounds a lot like politicians, doesn’t it?”

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