Bowerbirds, art and aesthetics

Bowerbirds are perhaps the most intriguing artists of the bird world. Their beautiful constructions are built purely to impress females (they are not nests, as often mistaken to be). One bowerbird, the Great Bowerbird, creates a particularly fantastic bower: in addition to building a symmetrical avenue made of carefully placed twigs, he also rearranges the objects on the ground (known as the ‘court’) around the bower. These objects are not strewn haphazardly, but instead carefully placed according to a system. First grey and white objects (often stones, shells, bones or man-made objects like bits of plastic) are placed on the court by their size, such that smaller items are placed closer to the avenue of the bower and larger objects are placed further away. On top of these drabber ornaments, brightly coloured objects are placed in specific locations that only the bower-builder could tell you the importance of (when a researcher moves one of these carefully placed objects the bowerbird quickly returns it to its ‘correct’ position).

Female bowerbirds move from bower to bower, inspecting male bowerbirds’ creations and the males themselves. Females often stand within the avenue of the bower, from which they can peruse the court and the male (who will display to her from there, often throwing his more brightly coloured objects around). Interestingly, the gradient that the male creates through placing objects in size order may act as a visual illusion from this angle, so that the female sees particular objects (and the male) as larger than they are in reality. One thing we know for sure is that females prefer males who have created steeper size gradients through their arrangement of the grey and white objects.