Birds
Rock Pigeon
Columba livia · also called rock dove, common pigeon, feral pigeon
The rock pigeon is so common in cities that most people never look at it twice — but it is one of the most remarkable birds humans have ever lived alongside. It was the first bird we domesticated, it flew military dispatches through two world wars, and it can find its way home across hundreds of kilometres of unfamiliar country.
Overview
The wild ancestor, the rock dove, is a bird of sea cliffs and rocky inland gorges from the Atlantic coast of Europe and North Africa across to India, nesting on ledges and in caves and feeding on seeds in nearby open country. Domesticated for at least 5,000 years, it has since spread worldwide as feral pigeons — the birds of city squares, bridges, railway stations, and grain stores, treating ledges and eaves exactly as their ancestors treated cliffs.
Navigation
The pigeon’s most studied ability is homing. A trained bird released far from its loft, in a place it has never been, will circle briefly and then set off in roughly the right direction, covering the distance at around 80 km/h. It does this by combining:
- a magnetic sense for compass direction and probably a positional “map”;
- the sun, using an internal clock to correct for its movement;
- landmarks learned around home;
- smell, building a map of which odours the wind carries from which direction;
- and possibly infrasound, very low-frequency sound produced by landscape features.
Crop milk and fast breeding
Pigeons can breed year-round wherever food is steady. Both parents produce “crop milk,” a protein- and fat-rich secretion sloughed from the lining of the crop, and feed it to the one or two chicks (“squabs”). This frees pigeons from needing an insect flush to raise young, and a city pair may raise several broods a year.
Intelligence
Pigeons perform strikingly well on cognitive tests: distinguishing artistic styles and individual faces, categorising objects, learning small “vocabularies” of written words, remembering large numbers of images over long periods, and being trained to detect cancer in scans. At least one study reports mirror self-recognition, otherwise documented in only a handful of species.
Status
As a species, Columba livia is Least Concern — the feral population is vast and secure. Paradoxically, the truly wild rock dove is in trouble in many areas, its populations diluted by interbreeding with feral birds and reduced by changes in farming. In cities, pigeons are often treated as pests for their droppings and their numbers, but culling is largely ineffective; limiting food and blocking nest ledges is more durable.
Rock Pigeon: common questions
How do homing pigeons find their way home?
With a layered set of tools. Pigeons carry a magnetic sense that gives them a compass and probably a rough map of where they are; they use the sun's position (corrected by an internal clock) as a second compass; they build up a memory of visual landmarks near the loft; and they use their sense of smell, learning the "odour map" of the winds around home. There is also evidence they can hear very low-frequency infrasound generated by terrain and use it to orient. Which cues dominate depends on the weather, the distance, and the individual bird.
Are city pigeons and homing pigeons the same bird?
Yes — all are Columba livia. The wild ancestor is the rock dove, a cliff-nesting bird of coastal and mountain crags. Humans domesticated it thousands of years ago and bred it for meat, for message-carrying, for racing, and for hundreds of ornamental "fancy" breeds. The pigeons in city squares are feral descendants of escaped and released domestic birds, which is why they nest on ledges and window sills — to a pigeon, a building is a cliff.
Did pigeons really carry messages in wartime?
Extensively. Before reliable radio, armies used tens of thousands of homing pigeons to carry messages from the front. A pigeon called Cher Ami is credited with saving a trapped US battalion in 1918 after being shot but still delivering its message; another, G.I. Joe, is credited with preventing a friendly-fire bombing in 1943. Thirty-two pigeons received the Dickin Medal, the animal equivalent of the Victoria Cross, for service in the Second World War.
Are pigeons intelligent?
More than their reputation suggests. Pigeons can distinguish paintings by Monet from those by Picasso, learn to categorise objects and even recognise written words, remember hundreds of images for years, tell individual human faces apart, and — in at least one study — pass a version of the mirror self-recognition test. They have been trained to spot tumours in medical images with accuracy rivalling radiologists.