Spring is the time for the birds to start their courting rituals, and that includes one of the most interesting, the bowerbird. Male bowerbirds court potential mates by building a complex bower of twigs, sometimes up to a metre high, and surrounding it with brightly coloured items. The satin bowerbird is particularly fond of blue, and they’ll fly up to 10 km to a picnic ground for blue straws and bottle tops.
They’re also quite adept at thieving, too: while one toothbilled catbird is off finding leaves for its display court of leaves on the forest floor, another may help itself to a particularly attractive leaf (what constitutes an attractive leaf I’m not equipped to guess).
The most puzzling aspect of all this bower construction is this: what evolutionary advantage does it confer on the birds? They don’t use the bowers or the display courts for nesting sites, nor does this display demonstrate anything about the male bird’s fitness as a mate (aside from his sheer determination to build something quite useless). On the surface, it looks like nothing more nor less than art.
So why do they do it? And how has the behaviour evolved, over the millennia? That’s a question that continues to puzzle me – if you have an answer, please post a comment!