E38. You have pulled one out of a jacket sleeve at a bad angle, picked one up on a walk, and you are almost certainly within arm's reach of a few thousand of them right now. Dr. Cody Limber, who recently finished his PhD at Yale, spent it taking growing feathers apart one cell at a time to find out what they are actually made of. A feather is not a fancy scale, it does not grow the way you would guess, and after all this time nobody can say what the first ones were for.

In this episode, you'll hear about:

• The strangest things growing out of birds, and which of them actually count as feathers
• What a feather is actually made of, once you smash one into individual cells and read what every cell was doing
• What a feather actually is, whether it is alive or dead, how it is put together, and the coordination that color and pattern demand

All audio, video, and images in this episode are either original to Okay, But... Birds (© Okay Media, LLC) or used under license/permission from the respective rights holders. Media from the Macaulay Library is used courtesy of the Cornell Lab of Ornithology as follows:

• Eastern Whip-poor-will audio contributed by Bob McGuire, ML195774
• Red-bellied Woodpecker audio contributed by Wil Hershberger, ML306064
• Indian Peafowl audio contributed by Rounak choudhary, ML621021542
• Common Raven audio contributed by Gerrit Vyn, ML132161
• Mallard audio contributed by Mike Andersen, ML136504
• Double-crested Cormorant audio contributed by Bob McGuire, ML233274
• Zebra Finch (Australian) audio contributed by Vicki Powys, ML226233
• American Herring Gull video contributed by Steve Kelling, ML540908261
• Golden-winged Warbler video contributed by Benjamin Clock, ML476422
• Great Argus audio contributed by Arnoud B. van den Berg, ML71122
• Horned Screamer audio contributed by Paul A. Schwartz, ML58925
• Wild Turkey audio contributed by James (Jim) Holmes, ML73964601