The other day, as I trudged to a cash machine for money to get the boot on my car removed, I happened on two ducks (both grey) beating up another duck (white).
I mean they were pecking at the poor things head. Being the softy I am I tried to break it up since they were on land. I figured it was a dispute over food or something and it would end right away. Instead, as the victim fled for its life the other two chased him down, one grabbing the back of the victim's neck and plunging it underwater the other helping to push the head down.
Birds of other species rushed to the victim's aid and managed to temporarily break it up a few times. Every time they did, the white duck would fly for its life but get chased down and dunked. The other birds kept trying to help but they were too small and got scared when the grey ducks turned on them.
Eventually they managed to drown the poor white duck. Poor thing :( It was pretty amazing to watch. I didn't know that ducks would deliberately execute other ducks. Huh.