Research: Hummingbirds See Colors Humans Can Only Imagine

With their reliance on color to find food and dazzle potential mates, escape predators and navigate diverse terrain, it’s no surprise birds have excellent color vision. New research that includes a University of Maryland biologist shows that hummingbirds can even see colors that combine the visible spectrum with ultraviolet light.

While humans have three color cones in the retina sensitive to red, green and blue light, birds have a fourth color cone that can detect ultraviolet light. Hummingbirds can see color combinations like ultraviolet+green and ultraviolet+red. Similar to purple, which combines two colors (red and blue) distant from to each other on the color spectrum, these ultraviolet combinations may form new colors that humans can only imagine.

In a study published today in the Proceedings of the National Academy of Sciences, a research team including UMD Professor Emeritus David Inouye trained wild hummingbirds to find a sugar treat by identifying ultraviolet combination colors. The birds could even distinguish between different shades of these combinations.

“The colors that we see in the fields of wildflowers at our study site—the wildflower capital of Colorado—are stunning to us, but just imagine what those flowers look like to birds with that extra sensory dimension,” said Inouye, who has an appointment at the Rocky Mountain Biological Laboratory (RMBL) in Gothic, Colorado, and co-authored the research paper.

To investigate how birds perceive their colorful world, the researchers established a new field system for exploring bird color vision in a natural setting at RMBL. They trained wild broad-tailed hummingbirds (Selasphorus platycercus) to participate in color vision experiments.

Read the full release here.