Why are some bird feathers blue?

I enjoyed the conclusion: “It’s simultaneously about physics, et cetera, but it’s really about, What do females want? It’s really about beauty.” So basically, male birds developed blue feathers to help them "get lucky"...I should have known!

Think I'll wear my blue hoodie before an attempted jog today.

I did not think this was a new discovery, that scientist already knew that the color in blue bird feather was structural rather than pigmentation. The most famous example of structural blue color is the Morpho Butterfly from South America, which has drab brown underwings which make it blend in when at rest, and brilliant metallic blue upper wing surfaces that flash in the sun as it flies. Other butterflies with similar structural coloration are the Great Purple Hairstreak of the S.E. U.S. (dark metallic blue), the Ulysses Butterfly of Australia (bright blue), and the Pipevine Swallowtail of th... [More]