Abstract
The kaleidoscopic colors and patterns associated with the avian world make it difficult, if not impossible, to select a single group of birds as the most spectacular. However, if one were faced with such a choice. it could easily be the waterfowl. As a long-time waterfowl enthusiast, I believe this selection to be a logical one for a number of reasons. Ducks, geese and swans not only often have brightly colored plumages and occur in a great variety of diverse shapes, sizes and forms, their lifestyles are such that sooner or later most people are exposed to them. Their relatively large size and highly social nature quickly draws our attention to them. The center of distributio of waterfowl occurs in the northern hemisphere, not in the tropics like many families of exotic birds. Some of the most beautiful and striking birds that ever graced this planet fall within this group. In essence, they combine many of the qualities that man finds aesthetically pleasing about birds, and of all the birds, waterfowl are perhaps the most fascinating to observe. There are relatively few individuals who will not admit they have at least a passing interest in those colorful and fascinating winged creatures known as waterfowl.
Ducks, geese and swans are all closely related and collectively are referred to as waterfowl or wildfowl. They comprise the avian family Anatidae . and consequently are sometimes called anatids by ornithologists. Although they resemble other groups of water birds in many respects, these similarities are merely superficial and have resulted because of their similar lifestyles. Many casual observers assume that all water birds are wildfowl but the 151 species of ducks, geese and swans found on the plant stand alone. Coots, grebes and loons, which also Live on water and are similar in profile, are not even distantly related. Stilts, sandpipers and avocets are shorebirds rather than wild fowl. Likewise, egrets, herons, flamingos and storks thought of as waders, while cormorants, gulls, penquins, pelicans, and puffins are loosely called "sea birds".
The closest surviving relatives of wildfowl are the bizarre screamers of South America ; so close in fact, that they occupy a position in the same order, the Anseriformes. This relationship is quite puzzling to non-biologists because screamers don't even remotely resemble a duck or a goose. Rath.er, they are more like huge chickens. Screamers are basically terrestrial birds and although they lack webbed feet, they are excellent swimmers. Some contemporary specialists believe that flamingos are also closely related to wildfowl and may represent an ancient offshoot. This opinion is based on anatomical similarities and the fact that much flamingo behavior closely parallels that of true waterfowl; even their feather parasites suggest an affinity with geese. Their vocalizations are distinctly gooselike and interestingly, newly hatched flamingo chicks are superficially remarkably similar to young goslings.
Ducks, geese and swans were among the first birds to be domesticated by man. Greylag geese, for example, were domesticated at least 4,000 years ago and may be the oldest of the domestic birds. Originally, waterfowl were undoubtedly maintained as a food source and later for ornamental and aesthetic purposes as well. Written allusions to waterfowl date back some 2,500 years and artistic depictions even earlier. Primitive rock carvings of swans fashioned by Cro-Magnon man in northern Russia have been unearthed as well as cave paintings of waterfowl in neolithic sites inhabited at least 20,000 years ago in Spain, France and Italy. Waterfowl are just as intriguing to modern man and the literature concerning them is probably the most extensive of any avian group.
From an economic standpoint. waterfowl are among the most valuable of all birds. They have probably been admired more and exploited to a greater degree than most other bird groups. One need only consider how dependent many people are on wildfowl and their eggs as a food source. In the western world the rearing of these birds for food is not of major importance, but in less affluent regions, particularly in Asia, domestic ducks are frequently as common as chickens in America. In North America and Europe, waterfowl hunting is a major sport, an industry that contributes billions of dollars to the economy each year. At the same time, the escalating conflict between hunters and protectionists has spawned a great deal of intense controversy in recent years.
Life on earth extends back into the spectrum of time for more than two billion years but man, as we presently know him, has only existed for S00,000 to one million years. Waterfowl are far more ancient; their origin dates back some SO to 80 million years ago, which makes them relative newcomers when compared to many other life forms. Birds originally evolved from reptiles and are sometimes referred to as "glorified reptiles" by nonsentimental paleontologists. It is believed that birds began to branch off from reptilian stock some l SO million years ago, shortly before the emergence of the first mammals, which also evolved from reptiles, but independently. Archaeopteryx is the earliest recognized avian fossil, dating from the Jurassic Period approximately 140 million years ago. Undoubtedly there were earlier birds or birdlike creatures, but remains of these have yet to be discovered.
Fossil remains of waterfowl and other birds are scarce since they are relatively frail creatures; their bones are fragile because most are hollow, a condition necessary for flight. Therefore, avian bones do not stand the test of time very well. In fact, most fossil waterfowl species have been described mainly from only a few disarticulated bones. The earliest recognizable wild fowl fossil on which most experts agree upon comes from the upper Eocene Period, dating back some 40 to SO million years. Avian paleontologists have identified about a hundred ex tin ct forms, including one family, two subfamilies, 22 genera, 92 species and three subspecies.
The never-ending process of evolution has been particularly productive with birds. Thousands, and perhaps millions, of species have evolved over the years only to ultimately disappear, and today there are approximately 8,650 living species of birds divided into 27 orders and I 55 families. The anatids comprise but one of these orders and families, but they are among the most divergent yet homogenous of all bird groups. While ducks, geese and swans range in size from the tiny pygmy goose weighing but ten ounces to the massive trumpeter swan which may exceed 30 pounds with a wing span of 8 to IO feet, all species are easily recognizable as waterfowl.