What Makes Hummingbird Feathers So Shimmery?

Male ruby-throated hummingbirds have shimmering crimson throats when the sun hits them just right. His bright green head shines! Besides ruby-throats, other hummingbirds have lovely feathers.

The Hummingbird Handbook author John Schewy says, “Hummers vary greatly in color and arrangement of their iridescent parts. Even among the few US-wide hummingbird species, the color variety is astounding.

Male Allen's and rufous hummers have flashing red-orange throats. Anna's male hummer has a stunning magenta throat, face, and crown. Costa's hummingbird, whose neck feathers taper into long mustache-like points on each side, and a royal purple head.

Birders Kenn and Kimberly Kaufman explain. It’s true. In an Anna's or ruby-throated hummingbird, the back feathers are not green and the neck feathers are not red. They're structural hues.

Though dull and black, the feather is coated in transparent layers of prism-like structures. They bend light to reflect specific colors. Because of this, colors can appear to alter. Red throat feathers can seem orange, gold, or green depending on light angle.

Birds & Blooms reader Steven Hogan asks, “Why do ruby-throated hummingbird feathers appear black sometimes?”

The gorgeous iridescent colors of some hummingbird feathers have a surprising source, explain Kenn and Kimberly Kaufman. Although the feather is drab black, it is coated by a thin coating of transparent cells that reflect light in specific patterns, like a prism.  

Light hitting the feather at the appropriate angle reflects dazzling red, violet, or green, depending on species. As the angle varies, a ruby-throated's neck can look gold or greenish. Feathers seem black without direct lighting.