Then he sent out a dove to see whether the waters had receded from the surface of the ground.
Genesis 8:8 TLV

The dove followed the raven to check to see if life had returned to earth. It would not be satisfied with bare ground, but would require something living to eat and in which to nest. A barren earth would be unsuitable for both dove and man.

The raven represents death and evil. The dove represents life and good. The raven is like the priest who first examines the leper. The dove is the same priest who examines the leper on the 7th day to see if he is clean or not.