God’s classification is flying creatures. The Hebrew ‘ôph, covers all types birds, bats and pterosaurs (the now extinct flying lizards). Again this is in contrast to evolutionary ideas that birds evolved from land creatures. Flying creatures have such unique characteristics that baffle any other explanation other than a creator-God as set out in this chapter.
Where do these creatures fly? We are told: above the earth in the open firmament of heaven. The Hebrew conveys the idea of the face, or surface of the expanse. To an observer on earth looking up they do fly in the surface of the expanse in the sense of being in the nearest part of the expanse which stretches all the way to deep space. They are clearly below where the stars are, which are set in the expanse.
At the end of this Day fifth, God saw that it was good, as the seas teemed with life and the air peopled by birds, with trees and shrubs and grass to feed, shelter and nest in.