Of a male Ruby-throated Hummingbird. While my backyard feeder never attracted a male I decided to drop by Riverwood Conservancy in Mississauga as I knew from last year that it was a great place to see them. Well I wasn't disappointed and so many others who were there in the morning. Here are some photos of male showing various shades of red coloration of its throat.
All photos are of the same bird, only difference is the angle at which the photos were taken. The first three three photos are from a sequence of shots I took. As the bird approached the flower of Beebalm plant its angle with respect to the sun changed slightly and that was enough to change the color of its throat (gorget) from dark to red. The last photo was when the bird briefly faced me, showing its ruby red throat.
The physics behind this change of color is very comprehensive. In simplest terms, Hummingbird feathers have stacks of hollow melanin granules (air bubbles) that reflect and refract light differently depending on the angle they enter and it changes between ruby red to almost black as seen in these photos. The color reflected is determined by the size and shape of the granules, for this hummingbird it just happens to be red.
