This is what Cathy saw:
There are house martin’s nesting at our house and a black bird came along fighting with the Martin knocked 3 baby’s out of their nest, sad but true.
I never cease to be amazed at what birds do to other birds. I have a few blackbirds in my garden and they are one of my favourite birds. I would never ever have thought they they would fight with a house martin.
Does this happen often in the wild?