Why do Beijingers like to keep pigeons?

My grandfather is a native of Beijing, a long time ago his family has a yard, the yard is somewhat like a courtyard, there are many neighbors around, in their yards will keep some pigeons, then I asked them why they keep pigeons, my grandfather said that pigeons symbolize peace, and at the same time every day to raise pigeons to give them food can also make their own cultivation, so this is for the Beijing people are also sort of It's a habit for Beijingers.