10 Of this dove, the dove of Noe, according to some, was in part a figure. For as in his time by means of wood and of water there came salvation to themselves, and the beginning of a new generation, and the dove returned to him towards evening with an olive branch; thus, say they, the Holy Ghost also descended upon the true Noe, the Author of the second birth, who draws together into one the wills of all nations, of whom the various dispositions of the animals in the ark were a figure:— Him at whose coming the spiritual wolves feed with the lambs, in whose Church the calf, and the lion, and the ox, feed in the same pasture, as we behold to this day the rulers of the world guided and taught by Churchmen. The spiritual dove therefore, as some interpret, came down at the season of His baptism, that He might show that it is He who by the wood of the Cross saves them who believe, He who at eventide should grant salvation through His death.
Source: Catechetical Lectures (New Advent)