3 ms·

https://en.wikipedia.org/wiki/Structural_coloration https://en.wikipedia.org/wiki/Structural_coloration seems like a decent explanation.

• User23 2y ago
  The best explanation I’ve read is Feynman’s delightful QED.
  • Myrmornis 2y ago
    Haha OK, some avian plumage enthusiasts might find that a bit of a detour though!