Nature Notes
Messenger Pigeons Carry Long Historical Human Connection
By Patricia Martin

Just the other day I received a note and a photograph from Clark Bloswick, who had seen a pigeon hanging around the State Park maintenance barn for more than a week. He said that it was quite tame, and he thought that it might be a racing pigeon as it had a band on each of its legs. Pigeons, or as they are more properly called, rock doves, are familiar to most people. Technically there is no difference between doves and pigeons, and these birds are often called homing or carrier pigeons.

Rock doves come in a variety of colors, from iridescent blue gray, to red, white, or tan. No other "wild" bird varies as much in coloration, which is the result of semi-domestication and extensive inbreeding over time. They usually have a white rump and orange feet and often have two thick broad bars across each wing. In flight the rock dove holds its wings in a deep "V" while gliding. They're about a foot in length with a wingspan of about 28 inches. The song they produce is a soft, repetitive cooing "coo-a-croo, coo-roo-cooo" or "cock-a-war" or "coo-cukcuk." These birds are impressive in flight, gliding most of the time and often wheeling in the air. They can fly faster than 85 miles per hour. They even glide to land. These pigeons are generally gregarious, often being found in flocks when roosting, feeding, flying, and even breeding.

Rock Dove. (Photograph courtesy of Clark Bloswick)

Rock doves are year-around residents of Michigan, particularly living in urban areas, railroad yards, and agricultural areas. These doves are adapted to human habitation. In cities, during the winter, they often can be found near underground heating ducts and parks, where people drop food. In addition, they now build nests on ledges in barns, bridges, buildings, or towers. In the wild, their natural nesting sites are cliffs and ledges. The flimsy nest is composed of sticks, vegetation, and grass, is in a saucer shape, and generally is not lined. The parents produce two white, 1.5-inch-long eggs, which they both incubate for a period of 16 to 19 days. The young are fledged in 25 to 26 days and the young can produce their own brood in six months. These birds may lay eggs year-around.

The young of rock, morning, and other doves are fed by their parents what is commonly called "crop milk." This special secretion is produced by a sloughing of fluid-filled cells from the lining of the crop, which is a thinwalled, sac-like food storage chamber that projects outward from the bottom of the esophagus. The crop allows the birds to gather and store food rapidly, which minimizes the time that the birds are exposed to predators. These organs are especially developed in pigeons and game birds. Unlike mammals, both sexes can produce this "milk" for their brood. The "milk" is extremely nutritious. It contains more protein and fat than cow or human milk, and is usually the exclusive food for the nestlings for several days after hatching and the squabs are fed it for more than two weeks. As they develop, the young begin to eat adult food and begin to glean grain, seeds, and fruits off the ground. They also will occasionally eat insects and green leaves.

Rock doves were introduced to North America in the early 1600s and have settled in cities, towns, and farms. They're probably the most common bird in cities. It is believed that rock doves were domesticated from Eurasian birds as a source of meat in about 4500 B.C. For centuries rock doves have been used as message carriers. The early Romans are said to have used the dove to carry the news of Caesar's conquest of Gaul back to Rome. The legend says that rock doves brought the news of Napoleon's defeat at Waterloo to England days before the messages sent out by horse and ship arrived. One of the reasons for their use as messengers is their studies, it has been shown that pigeons are capable of detecting the Earth's gravitational field and can use it to orient and possibly navigate. Exactly how the birds manage to sense such weak electromagnetic fields is unknown. In general, birds are much more sensitive to these fields than are humans. In addition, homing pigeons have been shown to use their sense of smell for at least short-distance orientation to return to their lofts. It has been shown that birds recognize land, water formations, and even manmade structures to orient themselves. The position of the sun and the stars help give them directional information. Most scientists have concluded that rock doves use more than one source of information to guide them, either in migration or in

used as food and messengers, rock doves have also been pets, used as scientific study specimens, and as racing birds.

Because of their long association with humans, they've been woven into the fabric of our culture, such as the dove as the symbol of peace or the Holy Spirit. They've been memorialized in paintings, poetry, and songs. Sometimes when we see them in parks and cities, or even here on Mackinac Island, I don't think we often appreciate the long relationship that we've had with these birds.

Trish Martin is a year-around resident of Mackinac Island, has earned a master's degree in botany from Central Michigan University, and owns Bogan Lane Inn.