The animal on the cover of Vagrant: Up and Running is a blue rock pigeon (Columba livia), also known as a rock dove or simply a common pigeon. Given the pigeon’s ability to nest in open or semi-open environments, this species thrives in cities all over the world. Rock pigeons are generally monogamous, with each breeding pair caring for two chicks (called “squabs”) each season. Males and females look almost identical, and both share distinctive iridescent green and purple feathers around the neck and breast.

Rock pigeons differ from other pigeon breeds, like homing or carrier, in that they do not generally leave their local areas. In the past, some species of Columbidae pigeons and doves have been used to carry messages over long distances. Although they started out as a domesticated European pet, escaped rock pigeons established themselves in urban areas and the population exploded. Now, the number of feral rock pigeons in Western Europe alone is above 20 million.

Because the pigeon has almost no natural defenses, it has become prey for a wide range of raptorial birds. In particular, peregrine falcons and Eurasian Sparrowhawks have come to rely on pigeons for 80% of their diets; this has allowed these large birds to continue to exist in and around major cities. In North America, the pigeon must avoid opossums, raccoons, red-tailed hawks, several species of owl, and cats.

Although pigeons cannot generally contract or transmit human diseases, prolonged contact with their droppings ...

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