Birds would come to eat the flesh of the defeated ones (chapter 19)

Then John saw an angel standing in the sun.  This angel called with a loud voice to all the birds that fly in midheaven, “Come! Gather for the great supper of God!”  These birds were to eat the flesh of the kings, the captains, the mighty ones, the horses, their riders, the free-men, the slaves, the small, and the great.  Have you ever seen birds eating dead bodies?