How are birds' feathers waterproofed?

22nd July 2009

Asked by: Oliver Lai, Port Louis

Birds pick up oil on their beaks, by rubbing against the uropygial or preen gland near the tail, and then rub it over their feathers. This coating insulates the interlocking barbules in the feather. As water cannot penetrate through the oil coating, the feather is waterproof.