Ive had birds fly by real close to me, usually when im messing around with my frequencies.
though it depends what type of bird.
reading the movements of birds can be traced back to early civilizations, I think the most famous practitioner of this art is Teiresias, the a prophet of Thebes. being a blind man a young boy described the flying patterns of birds to him. He was then able to make accurate predictions.
overall, small birds bring smaller omens, while the large birds offer much more important messages.