Yes definitely that is what it refers to. The Earth is stolen by “powers” represented by people and their virtues. When all the virtues are lost and they cannot be fought for, the Earth will fail despite anything, any power. This is represented by the people/characters and their heroic other egos, which are bestial and the fact that their relationships are the cement of the civilizations of the earth throughout time. But they are being divided by variable and evil forces. The two brothers represent that they are both birds, but one is mortal somehow and the “divine” bird is an angelic bird, who falls to earth injured to fight in the quest to turn back the abandonment of the earth to evil powers. I haven’t read yet who wins because there is too much text on the actual book concerning its scholarship, it doesn’t really settle the ending of the story.