Hummingbirds See Red
Red flowers and feeders are rich sources of food for hummingbirds, but it turns out that it's the nectar, not the color that makes the most difference.
This story comes to you through a partnership between Audubon and BirdNote, a show that airs daily on public radio stations nationwide.
[audioplayer:141271|align:right|caption:Hummingbirds and what they see, by BirdNote]
The hummingbird we hear zipping by is likely seeking out red blossoms, or making a beeline for a backyard nectar feeder accented with red plastic.
What is it about hummingbirds and the color red? Red flowers, and of course red feeders, are often rich sources of food for hummingbirds. The color red often signals high-octane fuel for their intensely active way of life.
The hummingbirds’ sense of color is due to the dense concentration of cones in its retina. The cones themselves contain pigments and oil droplets in shades of yellow to red, which seem to act like filters. The filters appear to heighten color sensitivity in the red to yellow range, while muting colors such as blue.
But it turns out that it’s the nectar, not the color that makes the most difference with hummingbirds. By varying the nectar content of flowers, researchers were quickly able to switch hummers from a preference for red to a preference for the most nectar-rich flowers, regardless of color. So even though hummingbirds’ eyes have a heightened sensitivity to colors in the red to yellow range, the little sprites are fast learners and will go to where the nourishment is.
Listen to any episode of BirdNote again on our website, BirdNote.org. I’m Michael Stein.
Sounds of the Rufous Hummingbird provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Wing sounds recorded by G. A. Keller CD 52 T9; call while perched CD 2 T 22 G.A. Keller.
Ambient sounds provided by Kessler Productions.
Producer: John Kessler
Executive Producer: Chris Peterson
© 2013 Tune In to Nature.org May 2013 Narrator: Michael Stein