This audio story is brought to you by BirdNote, a partner of The 吃瓜黑料. BirdNote episodes air daily on public radio stations nationwide. 5826 Transcript: This is BirdNote. Feathers are miraculous structures. Especially the long, strong feathers of a bird’s wings and tail that make flight itself possible. But after about a year, constant use and exposure to the elements mean they have to be replaced. So how do you replace the roughly 20 feathers in each wing that are essential to flight, without becoming earthbound? Many birds molt a few flight feathers at a time, wait until new ones grow in, molt another few, and so on. Usually the same feathers on each wing at the same time, symmetrically. So in summer, a raven that’s molting might look a little ragged in the same part of each wing. For ravens, a molt can take up to six months. For smaller birds, closer to two. But — crucially — they can still fly. Waterbirds like ducks and loons...