The color blue is commonly found in nature. Many varieties of birds found in our own backyards exhibit a shade of blue. While some colors in plumage are the result of a pigment, the blue in feathers is due to their structure. Light refracts off of the feather proteins and we see it as blue. It seems likely that birds have evolved blue feathers for different reasons than their fellow feathered friends have evolved yellow or orange plumage. Like all other colors in birds, bright blue will likely serve to attract mates and more subtle blues will provide camouflage in certain habitats. Blue is a cool color often associated with calm. Perhaps this is why blue colored birds are among some of bird watchers’ most favorite.
One of the most obvious birds to open this discussion is the Eastern Bluebird. As its name indicates, the Eastern Bluebird is prominently blue, with bright blue wings, tail and head. Like so many bird species, the male usually has a deeper blue than his female counterpart.
The Blue Jay offers another, somewhat softer shade of blue than the Eastern Bluebird. Most of its upper body including its head, back and tail are blue, but the Blue Jay’s underbelly is a downy white. Though in their capacity as “the forest’s sentinel,” it seems that the calming aspect of the color blue cannot be attributed to Blue Jays without some reservation.
Closely related to the Blue Jay, Florida’s Scrub Jay also boosts blue plumage, if not as prominently as its cousin. Its gray-brown back and gray underbelly serve to further highlight the blue feathers of its wings, tail and head.
Several different varieties of swallows have some blue in their plumage. However, male Tree Swallows not only demonstrate a vibrant blue but also another interesting aspect of structural color, iridescence. Iridescent colors in birds are created because of light refracting from feather barbules. This effect works like a prism, splitting the light into component colors. In this case, as we view the birds from a different angle, the color changes.
The Great Blue Heron has a blue-gray body with darker blue stripes on either side of its head. This shade of blue-gray is much more subtle than the colors of the other birds discussed in this post. The sheer size of the Great Blue Heron makes its blue seem more prominent than it otherwise would be. The muted coloring most likely developed to help the Great Blue Heron blend into its wetland habitats.
Much the same as the Great Blue Heron, the Tricolored Heron is a muted blue-gray color. However, its coloring is a darker and richer shade of blue than its fellow heron. The Tricolor Heron, as its name suggests, is not completely blue in coloring. The blue is highlighted with purplish-red on both its wings and neck. But the Tricolor Heron’s plumage also as a strong similarity to that of the Tree Swallow, not in the shade of blue but in its iridescent nature.
As you can see, blue occurs in nature in a variety of hues for our viewing pleasure. Whether for mating advantage or camouflage or another reason altogether, we can thank the structure of the birds’ feathers themselves for the lovely shades we all enjoy.
To learn more about the parts of a feature, visit https://academy.allaboutbirds.org/feathers-article/2/