Project PigeonWatch
In the wild, all individuals of a species usually look much the same. Robins all have gray backs and red-orange breasts. All crows are black. But the pigeons around the world show remarkable color variation, just like cats and dogs. Why? They are all descended from the blue-bar Rock Pigeon, but over hundreds of years pigeons were selectively bred by humans for their colors, homing instincts, or racing abilities. Eventually, captive birds escaped into the wild to become the feral, common pigeon flocks we see today.
Feral pigeons have adapted to life in cities, in suburban parks, on beaches and on farms. They have had established populations in North America for 400 years. And despite this, their populations continue to have individuals of many different colors. No other feral animal has kept so many domestic colors for more than a few generations.
Scientists believe there are at least three possible explanations why there are so many colors of pigeons across the world:
- They don’t have many natural predators in cities. Predators tend to attack the “odd one out”. But in cities, there are few predators to eat the odd-colored birds. Therefore these birds may survive to breed and pass their unusual colors to the next generation.
- Food is abundant in cities. Food fights would be few, and all morphs would be able to survive and breed.
- Assortative mating. Maybe multiple color morphs continue to persist because city pigeons choose mates by their colors. Because colors are inherited, the colors of parents will determine the colors of their young.
Observations made by PigeonWatchers counting the different color morphs and recording the colors of courting pigeons in many different cities can help scientists learn:
- why pigeons continue to exist in so many colors
- which color morphs pigeons prefer for mates
Visit www.birds.cornell.edu/pigeonwatch for more details.
Image from Wickipedia.
