Feathers

Joe Meche is a member of the board of directors of the North Cascades Audubon Society and is in his eighth year as editor of the chapter newsletter. Joe is also a member of the board of directors of the Washington Brant Foundation. He has been photographing birds and landscapes for over 30 years and has been watching birds for more than 50 years.

Humans have had a long-time fascination with feathers and have utilized them to the fullest. Feathers have been used as decorations and adornments in many cultures; we’ve used them to dust our furniture and tied them to hooks to catch fish. We’ve written some of our most important historical documents with quill pens; and we’ve used feathers to line our clothing and bedding. There was even a time when style practically insisted that you wear a feather in your hat. Feathers add a wonderful array of color to our lives, especially in spring when colorful birds arrive from the tropics to breed in our area.

Feathers are the most prominent characteristic of birds and they are the only members of the animal kingdom with feathers. As a matter of fact, except for their beaks and bills, legs and feet, birds are completely covered with feathers—another marvelous example of evolution playing a role in form and function. No matter where you go or how actively you pursue birds, you can always find remnants of birds having been there, in the form of the feathers they leave behind. Whether they might have wafted in on the wind, were shed during a molt or just sit there on a trail as mute evidence to a recent predator kill, feathers are a common part of everyday life. Many of us try to identify feathers that we find and, in the case of the latter, we try to speculate as to which predator might have done the damage.

Birds developed feathers over millions of years, and their origins remain a subject of some controversy. Fossil feathers from the earliest flying specimen, Archaeopteryx lithographica, are practically indistinguishable from those of contemporary birds, so there is no hard evidence as to exactly how birds developed feathers. The link between birds and reptiles is well known. Feathers and scales are both composed of keratin and both are arranged in overlapping segments to protect the skin from wear and from the elements. Somewhere along the way, adaptive evolution stepped in.

Since feathers and flight are obvious connecting links, some surmise that the elongation of scales in certain species led to the eventual development of feathers to better enable birds to glide and eventually fly. The evolution of flight feathers was followed by the contour feathers that cover the body and serve to insulate birds from extreme heat and cold. Feathers, along with the development of hollow bones, reduced the overall weight of birds, leading to longer and longer periods of sustained flight.

Feathers are outgrowths of feather follicles, which originate in the skin, much like our own hair and hair follicles. The process actually begins while the bird-to-be is just an embryo. Through an amazingly intricate course of development, one of nature’s most spectacular products evolves. A cross-section drawing of the construction of a basic contour feather reveals just how remarkable feathers are. Equally amazing, and pointing toward the natural aerodynamic design of birds, is the fact that feathers grow out pointing toward the rear of the bird.

There are several distinctively different types of feathers that make up the total bird. Contour feathers cover the body, while the remiges and rectrices are the primary flight and tail feathers, respectively. Down feathers, semiplumes, filoplumes, powder feathers and bristles lie mostly beneath the contour feathers and are best seen when you might have occasion to have a bird in hand or while examining a specimen in a museum collection. Each of these feather types is complex and suited to the needs of the individual species, from raptors and diving birds to woodpeckers and passerines.

The complexity of design is even more pronounced in the structure of feathers. A close look at contour feathers reveals a central shaft with broad vanes on either side. As the word might indicate, contour feathers follow the outline of the avian body and, since these feathers are not an integral part of flying, are symmetrical. The remiges—the primary and secondary feathers of the wing—on the other hand, are asymmetric. In this design, the perfect airfoil is formed by the wing as the leading edges of the feathers are narrower, to literally slice through the air while the wider trailing edge provides the necessary lift required for flight. The rectrices, or tail feathers, are also asymmetric and serve to control direction and speed.

A series of hooks and hooklets, barbs and barbules serves to maintain the integrity of the flight feathers and keep them zipped together. With a feather in your hand, you can separate individual parts and then, just as a bird might, you can zip it back together. If you watch a bird that’s actively preening, you can see how carefully they maintain their feathers to keep them in top flying condition.

For birdwatchers, the colors of a bird are essential keys to field identification. Terrestrial animals pale by comparison to brightly colored birds, especially those in their finest breeding plumage. Three types of pigments—melanins, carotenoids and porphyrins—produce the variety of colors that we see. A range of conditions determines the colors of individual species. Some of the colors that we see are not really colors at all, but merely patterns of reflections and refractions of light that create the appearance of color. The main ingredient in feathers—keratin—sometimes exists in layers and creates iridescence in some birds’ feathers. In others, layers of melanin reflect with a wide range of colors. Just like a rainbow, the colors that we see are often relative to our angle of view.

Another aspect of feathers not to be overlooked is their incredible insulating qualities. Birds spend their lives exposed to weather extremes that humans could barely tolerate. Sea ducks that spend a lot of time on cold water are equipped with a layer of subcutaneous fat, and an almost impermeable layer of contour feathers that cover the dense layer of down that is closest to the skin. Man has created synthetic fibers for insulation but nothing manmade has ever equaled natural down. The light weight and high insulating values of down have been recognized by humans for centuries.

A favorite song of mine from the 70s was John Denver’s “Grandma’s Feather Bed.” It was always a fun song to play and sing along and, most importantly, I could relate to everything that took place during the day at my own Grandma’s house, leading right up to the feather bed as a final destination. Compared to my regular mattress at home, the feather bed at Grandma’s was a little bit of heaven. I’d literally sink into that mattress and feel the same thing that countless generations must have felt in the comfort of down. Down comforters are prized possessions in numerous households, including ours.

At one time in history, feathers were highly desirable as fashion accessories. The principal feathers that were sought were the long plumes of the large wading birds. These plumes were used to adorn women’s hats, and the wholesale slaughter of birds by plume hunters was instrumental in the origins of conservation organizations like the National Audubon Society. Early efforts of these organizations are credited with saving several species from being wiped out by hunters.

Feather maintenance is essential to birds. To control parasites, such as lice and mites, birds preen on a regular basis. They bathe in bird baths and puddles and also take dust baths. A few species take part in a phenomenon known as anting. More than 200 species of birds are known to practice anting by placing ants in their plumage. The formic acid secreted by the ants serves to eliminate parasites.

Birds utilize a number of other materials to rid themselves of pests. In fact, they have been known to rub coffee, vinegar, beer, and even cigarette and cigar butts into their plumage to find a measure of relief. Some birds have been observed to take an ant in their beaks and actively rub it into specific areas of skin that might be irritated, especially during the molting period.

Since feathers are not permanent, birds go through periodic molts to replace their worn feathers. Some waterfowl are rendered flightless during certain times of year when they are in the process of replacing their primary flight feathers. Birds also progress through a variety of plumages before reaching full adult breeding plumage. These are the times that pose the greatest challenges to a birdwatcher’s field identification skills. In a great number of species, the male and female plumages are different so, in effect, it’s almost like learning two species instead of one. As if that weren’t enough, many birds adopt winter plumage. Challenges abound!

There are numerous theories as to the origin of feathers and flight, and since there are no obvious clues, the debate will continue. Part of the problem lies in the fact that feathers are too perfect. They are perfect, but far from simple. They are the single most complex derivative of skin—much more so than the hair of mammals. Feathers are yet another of nature’s masterpieces and they are all too often taken for granted. §

“Well, I’d sit right there in my easy chair ‘til the cobwebs filledmy head,

Next thing I know I’d wake up in the morning in the middle of the old feather bed.

It was nine feet high and six feet wide and soft as a downychick,

Made from the feathers of forty-leven geese, it took a wholebolt of cloth for the tick.

It’d hold eight kids and four hound dogs, and a piggy we’dstole from the shed,

We didn’t get much sleep but we had a lot of fun in Grandma’sfeather bed.”

John Denver
1943 –1997