Dirty little secrets: "dress for success" is the key to the mating, game among Arctic ptarmigan.(Naturalists At Large)

Most birds act as if cleanliness really is next to godliness. Watch any bird for a while, and you will see that it spends a lot of time preening its feathers and bathing in water or dust. Feathers are essential for flight, waterproofing, and insulation, so it is not surprising that maintaining them is a vital part of a bird's daily routine. How to explain, then, the bizarre sartorial metamorphosis we have observed in the male rock ptarmigan, a species of grouse? In just a couple of days in early summer the male ptarmigan suddenly transforms himself from an immaculate, pugnacious white bird that stands tall on large boulders, to a filthy, bedraggled creature that skulks ...