The Bengalese finch is an aviary bird, bred over centuries for its attractive plumage. It comes in various combinations of white, black and brown. One particularly pretty version is silver. It is also prized for its gregarious and easy-going nature and its complex warbling song. Which is strange because the finch's closest wild relative, the white-rumped munia has a simple, predictable song as well being incredibly shy and easily upset. How could the finch, bred for its colour, have evolved these other elaborate traits as well?
Solving the puzzle of the Bengalese finch promises to throw light on a much larger question in biology: how nature creates complex things.