A single, lacy, white plume drifted past on the gentle current, aided by a wisp of wind. A glance downstream revealed its owner, an elegant wading bird with a dagger bill and stilt legs. As I lifted my gaze even higher, I could see a pair of idle gray smokestacks above the trees that lined the river.

Such incongruous sights are common along the Anacostia River as it slips on its tidal current back-and-forth through Washington, DC. Like other urban rivers, the Anacostia maintains vestiges of its natural beauty even in the face of enormous stress.

The handsome bird that produced the plume at my feet was almost all white. It had black legs and bill. A bit of unfeathered flesh below the eyes was yellow, and so were the feet that clutched a half-submerged tree. This extraordinary beauty was a snowy egret (Egretta thula), a medium-size wading bird common in coastal areas.

Male and female snowies look alike, so there was no way to know the gender of the bird I was viewing. During breeding season (February through July), snowy egrets develop some of the most beautiful plumes in the avian world. They are long, lacy and immaculately white.

During the late 1800s, the feathers from these birds adorned the hats of fashionable women throughout the United States and Europe. They were the hottest item in the millinery trade. In 1886, snowy egret plumes cost $32 an ounce: twice the price of gold.

Under immense hunting pressure, the birds were driven to the edge of extinction. Fortunately, a growing number of individuals decided that the wild birds were worth more than the prices their feathers were commanding on the open market.

By the end of the century, the effort to save the egret and the many other birds facing similar threats led to the formation of organizations such as the Audubon Society. Soon, a powerful citizen lobby was using its collective influence and wealth to protect birds through the purchase of sanctuaries and the passage of laws.

Snowy egrets are year-round residents of South America, the Caribbean and along both coasts in the United States. The northern limit of the bird’s year-round territory is the Chesapeake Bay, although the birds will migrate as far north as Maine and far inland during the breeding season. Snowies can be found in both fresh and saline waters.

Male birds begin the mating season by selecting a nesting site and undertaking the initial construction of a nest, usually high in a tree. He will engage in a number of breeding behaviors designed to attract a mate for the season.

When the female joins him, both continue with nest construction. At this stage, one of the birds will bring a stick to the nest, passing it off beak-to-beak to its mate for construction. The male does most of the stick foraging, leaving the female to construct the nest.

In peak breeding season, the yellow parts of the snowy egret flush, with the lores turning reddish and the feet orange.

The female will lay two to six eggs in a single annual brood. The chicks are helpless upon hatching. The parents must supply body heat to keep the little birds alive on chilly evenings and food for their rapid growth over the next three weeks.

Carnivores, snowy egrets consume a diet of small fish, aquatic invertebrates, lizards, snakes and the like. Unlike many species, they feed throughout the day.

Although the snowy egret survived extinction from the millinery trade, the birds faced a second threat from the widespread use of toxic pesticides in the middle of the last century. When the U.S. Congress outlawed DDT and put limits on other chemicals, the snowy egret population here rebounded. As similar laws were enacted in other countries, snowies revived there, too.

The solitary bird along the Anacostia River bank reminded me that the population of the birds is on the rebound throughout its range. These elegant birds are now common along many fresh and saline waters.

But the story is never quite over.

The Benning Road Powerplant — its rusting smokestacks looming on the horizon — was closed because its dirty emissions constantly violated Clean Air standards. Other coal-fired plants across the country, as well as cars, trucks and thousands of other sources of climate change chemicals continue to pollute. As sea levels rise and weather patterns are violently disrupted, snowy egrets face a new and more ominous threat.

I looked down into the murky waters of the Anacostia and saw a hazy reflection of myself. I was left wondering, can a band of like-minded citizens change behaviors and laws once again to save these magnificent birds (and innumerable other species) from this latest man-made threat? The answer seems as cloudy as the water.