Genesis 8:7

a raven The Heb. and LXX give the definite article, "the raven," which some have explained as the only male raven in the ark. But the article is idiomatically generic; cf. Genesis 8:8, Gesenius, Heb. Gr.126, § 4. The Israelite story records the sending, first of a raven, and then, on two successive occasions, of a dove. The Babylonian account records the sending first of a dove, which returned; then of a swallow, which returned; and lastly of a raven, which turned not back.

Noah, stranded with the ark on the highest point, is unable to see anything around or below him.

went forth to and fro Presumably it was preying upon floating carcases. The "to and fro" suggests the picture of its flitting backwards and forwards, near the ark.