When I was about eight I received, as a generous Christmas present from an aunt, an illustrated book about birds and animals. I must have paged through that book hundreds of times (it is still on my bookshelves), gazing in wonderment at the (black-and-white) photographs of all sorts of exotic species. One bird that fascinated me was the bower bird. The male of the species  builds a bower – quite a complicated stick structure – and then decorates it with various objects. As wiki puts it, ‘These objects — usually different among each species — may include hundreds of shells, leaves, flowers, feathers, stones, berries, and even discarded plastic items, coins, nails, rifle shells, or pieces of glass.’ I thought about the bower bird as I was on my way to Zaventum airport a few weeks ago. There are roadworks in one of the tunnels leading out of the city. As our car flashed by I just had time to see that the workmen had collected up about thirty fallen hubcaps and had decorated the walls of their hut with them. They were urban bower birds!