My first male indigo bunting! Pretty stunning, huh? Like the ovenbird, we let this one go because he was just passing through our urban site and would not remain there. Yesterday was a good day for migrants!
Interestingly, there is no blue pigment in any bird's feathers. If you look at a blue feather at different angles, it will appear different colors (black, grey, blue...). This is because both the color blue and iridescence in bird feathers are created by the nanostructure of the feather. The constructive interference produced in the layer between the hollow core of the tiny barbs making up feathers and the cortex is what produces the color blue (this layer is called the cloudy zone or spongy layer and is not present in all feathers). Iridescence, however, is produced in the barbules found on the barbs, by reflectors. Here's a great article that says it way better than me in Birder's World. Thanks again to Lisa Myers of Let's Go Birding for first pointing this interesting fact out to me and getting me thinking about what makes a bird's feather blue.
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