There it is - a rather ordinary looking Common Grackle that was nosing around my backyard yesterday. But when it turns just right in the sunlight and angles its body relative to my line of sight...wow! The rainbow of color almost rivals that of a Painted Bunting. Well...perhaps not quite that spectacular, but it is still pretty cool.
The grackle’s iridescent color is a result from the structure of its feather barbules and is produced by light wave interference - the mutual change that occurs when two light waves intersect. The light is only reflected at certain angles because of the way the barbules are twisted and flattened. The word “irides” means “rainbow” and comes from “Iris,” who in Greek Mythology was the personification of rainbows.
You’ll never look at a Common Grackle the same away again!
Common Grackle images © 2006 Mike McDowell
