This story is brought to you by BirdNote, a show that airs daily on public radio stations nationwide.
When a perched male Ruby-throated Hummingbird raises its head toward the sun at just the right angle, its throat glitters like a crimson spotlight. When it turns its head slightly, the bird’s throat no longer gleams. It appears colorless, dark.
A hummingbird’s brilliant throat feathers are called its “gorget” (pronounced gor-jit). The term comes from days of old, when a knight-in-armor wore a metallic collar—or gorget—to protect his throat. The hummingbird’s intense glint is the result of iridescence, rather than colored pigments. The bird’s throat feathers contain minutely thin, film-like layers of “platelets,” set like tiles in a mosaic against a darker background. Light waves reflect and refract off the mosaic, creating color in the manner of sun glinting off oily film on water.
"There he goes! Diving in display toward the female. He plunges downward al-most vertically, achieving tremendous speed. Then, he levels off and heads straight into the sun, which makes his gorget glow with iridescent brilliance." (The quote is from Alexander F. Skutch and Arthur B. Singer's The Life of the Hummingbird.)
See the Rufous Hummingbird's gorget at birdnote.org.
Hummingbird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Ruby-throated Hummingbird recorded by R.S. Little. Anna’s Hummingbird recorded by T.G. Sander.
Anna’s Hummingbird display “chirp” recorded by C. Clark and A. Varma, U.C. Berkeley. Ambient track recorded by Kessler Productions. BirdNote's theme music was composed and played by Nancy Rumbel and produced by John Kessler.
Producer: John Kessler
Executive Producer: Chris Peterson / Dominic Black
Written by Bob Sundstrom
© 2015 Tune In to Nature.org March 2015 Narrator: Mary McCann