By David Cronenwett
When we think of birds, the mind immediately turns to flight. That birds can fly and have adapted to a life of flying the world over is miraculous. Much of what allows the Aves taxonomic class to take to the air involves feathers. For a long while, the prevailing theory explaining the appearance of feathers among reptile-birdlike creatures of the Jurassic went like this; since flying was a way to avoid terrestrial predation, evolutionary processes selected feathers as a means to an end, that is, to support flight. This assumption was largely based upon the strikingly feathered Archaeopteryx specimen found in Germany in 1861. Newer fossil evidence beginning with multiple discoveries in China during the late-1990’s completely reversed this long held belief and demonstrated that flight was in fact, an incidental benefit of a feathered body.
The origin of birds (and their feathers) begins about 200 million years ago in the late Jurassic era within a class of dinosaurs called Therapods. Tyrannosaurus-Rex, Velociraptor and many other of the bipedal predators in this group shared characteristics that we would recognize today as strongly bird-like. They were endothermic (warm-blooded), possessed strutted, lightweight bones, three-toed feet, a “wishbone” (furcula) and frequently, feathers of one kind or another. Very early feathers were simple, tubelike structures. Over time, species diversified and we begin to observe more complex feathers that followed, like those in the Anchiornis genus.
The reason proto-feathers appeared in the first place was likely a function of thermoregulation and later, displaying. Feathers with defined shafts, barbs and flat planes (called “vane”) could effectively insulate the body from cold and heat, deflect rain, signal for mates or hide an animal with its camouflage. Evidence from the ancient past show that many Therapods were brightly colored and densely feathered. The astounding discovery in September 2011 near Lethbridge, Alberta of Cretaceous feathers preserved in amber demonstrated that several species of dinosaurs with varying developmental stages of feathers, coexisted and shared habitats.
As these animals evolved, especially as they became smaller and lighter, the potential for flight drew near. Much research and speculation has taken place over the question of specifically how birds developed the ability. One hundred-twenty million years ago, ancient birds and their feathers were not completely up to the task; many of the flight movements necessary for proper lift and the asymmetrical-airfoil shape of primary feathers were not yet honed by evolution. Current thinking behind primordial avian flight is that feathered Therapods were excellent tree climbers; after much flapping, leaping and gliding came a first propulsive flight. Successive generations forced the adapted perfection we see today in avian anatomy and flying.
The physical structure of feathers, their composition and architecture, is remarkable. Made largely of keratin (the same material found in mammalian nails and hair), they are water resistant, durable, repairable and replaceable. They can also be stunningly colored, which has drawn the eye of humans from our earliest beginnings.
Raptors, especially eagles, are still held as spiritually powerful by traditional Native Americans. Because the birds soar in the realm of the Creator, as well as the superior arrow-fletching offered by their primaries, eagle feathers became some of the most culturally significant objects for hunting peoples in North America. In the tropics, vivid plumages were valued for their brilliance and rarity; colors that occurred nowhere else in nature could be found among the birds. Headdresses, elaborate capes and other accoutrements were created for adornment and ceremonial purposes the world over. The feather seems to be universally embedded in the human psyche as representative of air, light, flying, beauty, spirit, eternity. Given the nature of birds, their incredible evolutionary trajectory and our long and intimate association with them, this honor seems entirely appropriate.
A more recent story of feathers, well-known by those familiar with conservation history, is the rapacious and unregulated consumption of them by the millinery industry. In the 19th and early 20th century, millions of birds including ibises, herons, egrets, and untold others were killed each year to provide feathers for elaborate women’s hats popular in Europe and the United States at the time. (Interesting to consider, since most of the feathers utilized were from colorful, male birds, whose plumage was in part, to attract females) The scale of the trade and its aftermath is inconceivable to us today and was one of the critical factors in the birth of the American conservation movement, which included an organization known then as the “Audubon Society”. Around this time, state fish and game agencies were just being set up to restore the great legacy of wildlife in North America and were backed by law. Political momentum was growing for the creation of a system of refuges modeled after those established by Teddy Roosevelt in 1903. It is important to understand that a significant piece of this history and thereby our conservation legacy, belongs to birds and the feather.
Thinking of the immense arc of time it took to perfect the great diversity of feathers we know today, we are reminded of the sky, the beings that have taken to living there and how much richer our world is because of them.