Book 25, Question 79
Why are there so many pigeons in cities?
City pigeons are descended from rock doves, which nest on cliffs.
Building ledges are like cliffs, and people drop food crumbs, so pigeons thrive. They have been living with people for thousands of years. Pigeons are smart and can learn to recognize people and landmarks. Feeding them in big groups causes crowding and messes, so it is best to let them find natural food.