PEREGRINE FALCONS

On two consecutive days this week I was attracted to bird screaching up high. On the first occasion I could see what I thought were two crows harassing another bird but were unfortunately at distance. Second day and the same thing was happening but this time it was one crow attacking what I believed was a peregrine falcon with a pigeon in its talons. He troubled the falcon sufficient for him to release his dinner and the crow in turn followed the pray down towards the groung but out of sight. We have had peregrines nesting on a nearby water tower for a good few years now so I presume he was patrolling from there. Question: Is this a likely scenario? Would the crow proceed to kill and eat the pigeon? I have seen crows escort buzzards from their territory but never any thing like this.