Thanks. But I still don't understand why some types of doves are also classified as rock dove. What do they have in common?
The book says "毛色變化多樣,但通常藍灰色和有兩條闊黑翼帶"
I can see two broad wing bands here in the picture below (december,2010 Lok Fu, Canon Powershot SX210 IS), but I cannot find any band in that white dove above. Can someone please explain?