In the Book of Genesis, a raven was the first bird Noah released that did not return to the ark.
Genesis 8:6–7 says that Noah opened the window and sent out a raven after the waters began to recede. The raven went back and forth until the waters dried from the earth. Noah then sent a dove, beginning a better-known sequence of tests.
The dove first returned because it found no resting place. After seven days Noah sent it again, and it came back with a freshly plucked olive leaf. A later release did not bring the dove back, showing Noah that the land was becoming habitable.
The raven and dove have different narrative roles. Popular retellings often focus only on the dove and olive leaf, which can make the raven easy to overlook. The text does not say that the raven returned into the ark; it describes the bird moving back and forth while the waters remained.