Northern Flickers are one of our most colorful winter birds, but rarely do we get to see the golden highlights they hide under their wings and tail, and for which they were once named (formerly known as Yellow-shafted Flicker).
In their usual upright perched posture, the golden highlights are almost completely hidden. There is a hint of yellow barely showing on the tail.
But if you catch the bird in just the right light, you get a glimpse of the yellow underside of the tail, quite striking against the pale polka-dotted breast feathers.
In flight, we can see the hint of yellow that lines the shafts of the primary flight feathers. (The bird almost flew out of the photo, so I had to crop severely.)
The entire underside of the wings are the same bright yellow as the underside of the tail. But you have to be really quick to catch it as they dart from feeder to tree. The white rump patch is another visual signal that identifies the bird.
What possible purpose could this yellow coloration serve? Especially since it is so rarely visible? Whoever named this bird must have been impressed with the flash of color that barely flickers in your eye before it is gone.