Doomed?

Hard to make out in the picture but there is a little bird (I think it's a Great Tit?) sitting on the wire watching as a cat sits outside his birdhouse (tree to the right of the photo) having tried to stick it's paw in to get at the chicks inside. Mean cat. I felt too bad for the birds to leave it to fate so I went out and shouted at the cat but I fear it will be back...