I am very divided about this sort of thing.
I don't believe that a bird flying into the house presages a death, but that is probably just because I never heard that as a child.
However, I often know what is going to happen before it does, both good and bad things. It isn't something that always happens though,
I too have woken to find someone standing beside my bed. When it happened, I recognised him as my grandfather, so I wasn't frightened, just suprised as he had died four years earlier when I was fourteen. I cannot remember now whether his appearance was followed by a death.
My sister describe him exactly, as the person she saw during the night before our father's death, which we were expecting at the time. She had not recognised him, but hearing her description made me say, "But that was Grandpa, dear." My sister responded by saying, "Why should he come to me?" My response was that he had been very fond of her, that Daddy was his eldest son and the last of his three children to die, and that he probably knew how hard Daddy's death would be for my sister.
The last time I visited my sister, knowing full well that she was slowly dying of cancer, I distinctly felt my mother standing just behind me in the hospital Ladies' room. I didn't turn round, so I didn't see her, but I know to this day that she was there, even although she had been dead for fourteen years at that time.
This can all easily be dismissed as imagination, I do realise that, but personally I like to think it means that there is some kind of existence after death. Those who do not share my opinion but find these things frightening, do not need to accept them as anything except figments of my or other peoples' imagination. There is after all no rational explanation or scientific proof.