From: Bill Thompson in Riverside California
Why, if Noah released the raven, breaking the pair, how did ravens return to populate? After all, didn't one mate "disappear?"
Dear Bill Thompson,
The raven didn't do its appointed task; rather, it flew "back and forth (from the ark) until the drying of the water from the land." (Genesis 8:7) So, the pair was never broken up.
Furthermore, the female raven may have already been "pregnant" with a fertilized egg. Some indeed suggest that, knowing this, Noach chose specifically the raven.
As for the dove, which did fly away, the verse says that Noach took seven of each kosher species of bird aboard the ark; thus, there was no concern of doves dying out, as there were six left.
Still, I have heard a midrash to the effect that this dove was reunited with its mate after all the birds were released from the ark.
Genesis 7:2,3; Rashi, ibid. Genesis 8:12 See Tikunei Zohar, Esrin V'chad V'esrin, 58b