It is the part of the bird that is not in the sky. I can swim in the ocean and yet remain dry. What is it?

Question

I can fly like a bird not in the sky which can always swim and always dry. I say goodbye at night and morning hi I'm part of you what am I? I follow and lead as you pass. Dress yourself in black my darkness lasts. I flee the light but without the sun. Your view of me would be gone.

Answer 1

A bird's shadow