Started feeding wild birds. peanuts. mixed seed . fat-.?

got squirrels too, but there is enough to go around. today saw a robin. a wren ( for the first time ever) blue **** and another bird with black and white on it's head. dont know what that bird is. it is not in my bird-book . got blackbirds and thrushes too. so put out seed-fat-mixture on the lawn. what is the the bird with black and white on it's head please/anyone know?