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.