Life in the Box: Green Birds


This morning I saw a female goldfinch in a yellow tree. They matched. That got me wondering: Why aren’t there more green birds?

Okay Google: Why aren’t there more green birds?

Google: There is a lot of green in nature due to chlorophyll that turns sunlight into plant food. If birds want to be green, they have to be more creative.

Huh. That is a weird quote. More creative birds? Well anyway, you’d think that things like green camouflage would save birds’ lives. I can understand the birds with brown colors—they match branches and soil colors, but how does a cardinal even exist? They should stick out like a target sign!

Okay Google: How do cardinal red birds even exist?

Google: I’m sorry I don’t understand.

What Birds See

Okay Google: What are the most common colors of birds?

Google: Red and pink: Hummingbirds; Orange: Orioles, Hummingbirds; Yellow: Goldfinches, Warblers, Hummingbirds; Blue: Bluebirds, Jays.

Okay Google: Do birds see in color?

Google: A Yale study, published in Behavioral Ecology, says that birds see in more colors than their plumage because of receptors in their retinas that see in the ultra-violet range, but also see colors that are invisible to humans.

What Humans See

Okay Google: What colors do humans see?

Google: We have three color receptors in our eyes roughly Blue, Green, and Yellow.

Huh. Birds with xray vision… and more receptors in those tiny little eyes than our big ones. Who’da thunk? Aha! Maybe their predators see in tonal values, not color!

Okay Google, tell me:

Dogs and wolves: See in shades of yellow and blue, but lack receptors to see in the range of green to red.

Cats: See in shades of blues and grays, but some say they see in yellows, too, like dogs, but with less saturated colors in that range.

What Dogs and Cats See

Huh. So a dog or cat could see a yellow bird in a green tree, but not in a yellow tree. And they could see a red bird in a yellow or white tree but not a green tree. And they could pick out a bluebird in just about any tree. But they pretty much have to concentrate on something other than color to sense birds.

I learned something today. I’m humbled to know that birds see a lot more color than we do.

But I still don’t know why most birds aren’t green. Maybe like Google says, they need to be more creative. Or, maybe like the Yale study says, they’re evolving away from drab to become even more colorful than we know!

Nancy Heather Brown is a retired, Emmy Award-winning television producer whose career has included interviewing, writing, narrating and editing for a span of four decades. Today, she enjoys learning new things and reflecting upon the creative process and life issues, both inside and outside the box. Her opinions are her own, and are not necessarily those of this web site.  

Summary of Yale Study on Bird’s Vision