Bowerbirds are the incredible creatures renowned for the artlike displays the males craft to attract the females. Looking for all the world like an Andy Goldsworthy work, the intricately crafted cathedrals of twigs, scattered with colored petals are astonishing displays of craft. The birds have long been known to hunt down objects of a certain color to decorate the bower — but it looks like they might be doing something much more impressive: cultivating plants specifically for that purpose.
Cultivation of plants by non-humans is rare, but not unheard of. Ants, for instance, are pretty good at the whole farming gig. But every case we've seen of this has always been for foodstuffs — and here we have evidence of birds cultivating plants for aesthetics, not nutrition.
Researchers in Taunton National Park, Central Queensland observed a large number of potato bush around bowerbird bowers. But the birds weren't locating themselves near the plants, they were bringing the plants to the displays. The bush has bright purple flowers and green fruit, which the bird brings in order to attract a mate. When the fruit shriveled, the birds discard the seeds nearby, and kept the area clear of grass and weeds, and the plants grow. Since the birds stay in one place for up to a decade, they benefited from the ready supply of fruit and flowers.
Not only that, but the bowerbirds are picky about the plants they want, choosing fruit that's especially green — effectively applying selective pressure for a specific visual trait, and leading to a change in the appearance of the fruit.
Lead researcher Dr Joah Madden said:
"We do not believe bowerbirds are intentionally growing these plants, but this accumulation of preferred objects close to a site of habitation is arguably the way any cultivation begins. It will be very interesting to see how this mutually-beneficial relationship between bowerbirds and these plants develops."
It's an incredible discovery, and shows just one more way in which we're not as unique as we thought.
Image by University of Exeter