‘And I saw an angel standing in the sun, and he cried with a loud voice saying to all the birds that fly in mid-heaven, “Come and be gathered together to the great feast of God, that you might eat the flesh of kings, and the flesh of captains, and the flesh of mighty men, and of the flesh of horses and of those who sit on them, and the flesh of all men, both free and bond, and small and great”.'
Clearly the sight of this angel temporarily ‘blinded' John for he was standing in the brightness of the sun. And the angel's cry goes out to the birds of the air to witness the final judgment of God. A similar cry to this goes out in Ezekiel 39:17-20, compare Ezekiel 39:4. Ezekiel's vivid picture of the last battle ends with the full restoration of Israel to God and is followed in the succeeding Chapter s by the description of the descent of the heavenly temple on an unknown high mountain in Israel. It expressed a truth which was beyond his understanding, that that restoration would take place in Heaven, from where the heavenly temple had come, and where the heavenly temple would be central. A future life in resurrection was still something only primitively grasped at that time. That is why the prophets mainly expressed their hopes of God's triumph in earthly terms.
This cry to the vultures and scavenger birds is a vivid way of describing the awfulness of the judgment and its universal application. It is not to be applied literally. What the angel is really doing is declaring the certainty of total defeat for the forces of evil. (There may be a last battle, but if so it will be between earthly forces as they face the final judgments of God. God does not need to fight with men).