I have just seen two very angry blackbirds chasing a cat up the lane - the cat was terrified and was running like a bat out of hell! Presumably he had encroached on their nest - they were having none of it!
Good on them. I'm afraid, although I absolutely adore cats- that would be the one reason that would stop me having any more. Do not have the figures to hand, but the predation by pet cats on baby birds is much more than by magpies or crows, etc- and yet magpies and crows do it to survive- cats have their plate full when they get home.
The other day the crows were mobbing a red kite... and giving him a very hard time.
I have two male blackbirds that chase each other around my garden. It's big enough for both of them to have their own territory, yet the insist on invading each other's. Crows don't like birds of prey! We have a buzzard who circles above the hill opposite my house, the crows mob him mercilessly.
Last week there was a single rook chasing off a red kite over our garden, which was a pity as we have too many pigeons and welcomed the red kite. no doubt it will be back.The rooks are nesting near us in a few tall trees, but this wasn't a true mobbing, as there was only one!