If it were a blackbird like nearly all other blackbirds, then it would be all black, with a yellow beak. It is leucistic, which means an animal that has whitish fur, plumage, or skin due to a lack of pigment. Its shape and its beak says that it is a blackbird, but it is about ten percent bigger than a blackbird – unless the white areas are throwing of my sense of size. The last time I saw and photographed a leucistic blackbird – not far from here and a smaller bird – I wrote the following:
it is said that the reduction of pigment in leucistic birds causes their feathers to weaken and be more prone to wear. Leucistic birds are usually more conspicuous, which puts them more at risk from predators. There is also evidence that leucistic birds might be less acceptable to potential mates.
Well, yes and no. Being an hereditary deficiency, if the problem were that serious you would have thought that leucistic birds would have died out with no one to carry the defective genes.