A pearl-gray sky settled over the region. The milky air hid the sun's sharp brilliance like a soapy film covering my glasses. July and August lay ahead, but the District of Columbia's murky weather was already in full summer mode.

Seemingly immune to the heat, a handful of birds gathered under the feeders to pick through spilled millet. Bobbing heads atop graceful bodies maneuvered through the grass, efficiently gobbling up the tiny seeds.

Suddenly, all five of the birds shot up into the thick air and rocketed away on whistling wings. The mourning doves (Zenaida macroura) darted over the neighbor's yard and immediately came back to roost on the telephone wires suspended above the feeders. The threat was apparently imaginary and certainly short-lived.

Mourning doves have a small head, dominated by a black eye rimmed with a baby blue orbit. A black crescent forms the bottom border of the dove's auriculars, or ears. Smooth neck feathers give way to a plump body that ends in a distinctively long, narrow tail.

Although there are minor regional variations in color, mourning doves are mostly warm browns. The male's head and neck display a soft iridescence, and the tan of his neck and breast is suffused with a subtle pink. In both sexes, the wings are a uniform buffy-brown with black spots visible when the birds are at rest. The long, tapered tail has white tips edged with black except for the center. The bill is black and the feet are pink.

Our backyard doves are about 12 inches from the tip of their beaks to the end of their elongated tails. That's about the same length as its cousin, the city pigeon. The similarity ends there. Mourning doves are delicate, slender birds with 18-inch wingspans and typically weigh about 4.5 ounces. Pigeons weigh twice as much and have 28-inch wingspans.

In spite of their diminutive stature, mourning doves are the most popular hunting birds in the United States. When flushed, they jump into a vertical takeoff and can rocket away with extraordinary speed and maneuverability.

These attributes make them sporting targets for thousands of hunters. Each year, an estimated 30 million to 40 million mourning doves are shot. In spite of the huge numbers killed annually, the population continues to be stable, with an estimated 340 million birds found across the nation.

Mourning doves can live for more than a decade and can produce multiple broods annually. These factors, along with frequent adjustments in hunting limits, contribute to sustainable populations that help the species maintain its status as one of the United States's most abundant birds.

Mourning doves are found in open fields, brushy areas and suburban lawns. They can be found year-round in appropriate habitat. Their range extends across the entire lower United States. The northernmost Plains only host these birds during the breeding season.

As my backyard visitors illustrated, mourning doves eat seeds. Unlike most birds, they don't vary their eating habits during the breeding season, sticking with seeds for 99 percent of their diet. Ornithologists tell us that mourning doves will eat 12–20 percent of their body weight daily. That's the equivalent of a 150 pound person eating up to 30 pounds of food a day. No wonder they have that plump appearance!

The whistle of the dove's wings when it takes flight is distinctive. Air rushes over the feathers, creating the sound. It is based on the same principle that creates the sounds of wind instruments. With doves, though, it is the wing that moves through the air rather than the air being forced through a stationary instrument.

The sound we most closely associate with these doves, though, is a mournful coo that gives the bird its common name. The dove's long, drawn-out song sounds like a lament. To novice birders, it is sometimes mistaken for the hoot of an owl. In the creative language of a child, our 3-year-old friend captures the confusion. She calls these birds "owl doves."

This is Zenaida macroura, an avian species that can be described in clear, objective terms. But humans are rarely content to confine their views of the world so narrowly. Born and shaped by our own experiences, we add layers of meaning to scientific certainty. A curious 3-year-old hears an owl-dove. To the romantic, the bird's song stirs mournful memories, making it a symbol of sorrow. Some ornithologists see these doves as eating machines, while hunters see a challenging target. To many birders, mourning doves are delicate symbols of elegance that contrast with the crass bulk of their pigeon cousins.

As I squinted to bring my backyard mourning doves into focus, I realized that the haze was as much a function of my mind as it was of the weather. For humans, seeing always seems to involve more than mere optics.