Why do the scavenger birds come after the end-times armies are destroyed?

Les explains that the fowls flying in the midst of heaven are not birds in the throne room but the birds who fly in the air around us. These vultures and scavenger birds are told to gather to the supper of the great God, where they eat the flesh of kings, captains, mighty men, horses, and those who sit on them, and the flesh of all men, both free and bond, both small and great. This great conflagration falls upon the assembled armies, especially in the Middle East, and the birds of prey and scavengers come as a cleansing effect, getting the earth ready for the soon appearance of the kingdom. All the Old Testament speaks of this event when scavenger birds feast on the gathered armies, which is why it is called the supper of the great God. Les also notes a report that a major scavenger bird in the Middle East normally laid two eggs and had one brood per year, but that the same species suddenly doubled to four eggs, and it is more or less documented that this species is multiplying at almost double the normal rate in the Middle East, though he takes such claims with a grain of salt.