For the Birds Radio Program: Chickadee Color
To our undiscerning human eyes, chickadees seem to be black and white and gray, but they are far more colorful to other chickadees, who can see ultraviolet light.
Transcript
Thirty five years ago today, on March 2, 1975, I saw my first Black-capped Chickadee and instantly fell in love. The bird was a curious little guy who stuck around long enough for me to go through every page of my field guide in search of his identity. At the time, I’d have never been able to distinguish a Black-capped Chickadee from a Carolina Chickadee, much less recognize different individual chickadees. By the time I was hand feeding my backyard chickadees in Duluth, I could distinguish many individuals by their behavior—one would tap on the window to catch my eye when she was hungry, but despite her boldness, that chickadee never once alighted in my hand—I had to reach my cupped hand filled with mealworms to her where she was perched on a branch. She wasn’t scared of my hand—more than once I accidentally brushed it against her and she didn’t flinch or fly—and she took her time choosing what mealworm to take out of it, but she apparently was squicked out by the thought of actually perching on human flesh. Some chickadees were timid, others bold; some were choosey about which mealworm to take, weighing several before selecting one, while others just grabbed one and flew off.
One year a pair of chickadees nested in the box elder right outside our bedroom window. Both of them had plumage anomalies that made them easy to recognize and kept them at the bottom of the chickadee status hierarchy. The male apparently had scar tissue on his face or some other problem that had caused a patch of feathers near one eye to grow in at a weird angle, jutting forward instead of smoothed back. The female had lost her tail—probably to a predator—around the time she started nesting. Over the weeks they were raising young, her tail was growing back, slowly enough that I could pick her out until well after the young had fledged. Throughout that summer, I could identify “my” chickadees by those odd feathers. But other than those two individuals, I’ve always had trouble telling chickadees apart by their plumage.
Chickadees of course have no trouble recognizing one another. Although to our eyes individuals are virtually identical, chickadee eyes have no such trouble. It turns out that male and female plumages are quite different. The cheek patches are whiter and the bib larger in males than in females, and males have a brighter gray back than females. Chickadees can see at smaller wavelengths than we can, in the Ultraviolet range, and studies show that what we see as a white cheek actually reflects quite a bit of UV light.
Many chickadees stay mated as a pair their entire lives, something common in species with identical male and female plumage, but chickadees also indulge in quite a bit of hanky panky, or what ornithologists refer to as extra-pair paternity. This extra-pair mating usually happens in species with pronounced sexual dimorphism, so it’s interesting that when we expand our visual perception to include the range that chickadees can see, they turn out to be sexually dimorphic, too.
Birds can see and often hear things we cannot perceive at all. It’s exciting to look at our elegantly plain little chickadees—such simple black, gray, and white birds—and realize that there is much more than meets the eye—at least our eye. .