I can answer that for certain, as today I was sat watching the birds feeding on the bird feeder in my garden when two beautiful looking wood pigeons landed on my fence,first there was like a courtship thing pecking at each others beaks then pecking there feathers this carried on for about 3 minutes then the female sort of put her head down and bottom up ,the male mounted and about 3 seconds later it was all over, then they turned there backs on each other then flew off, honest no joking lol