What does the vulture represent in the novel, The Monkey Wrench Gang?

The vulture appears throughout the novel as a symbol of death or destruction. In the beginning the vulture is present and alert as the Glen Canyon Bridge is destroyed. It is also present as the foursome travel through the desert during the chase, as Hayduke completes his acts against the government, and as Hayduke's scarecrow is shot to pieces at the edge of the Maze.