I think that a couple of ideas can come out of this scene. Of the choices offered, I am more inclined to go with the idea of people attempt in vain to control nature through technology. I like this because the concept of "nature" can be applicable to both the natural world and the birds that are forming overhead. The tractor and its inhabitant represent an aspect of consciousness of supposed strength. The person can feel a level of power in their being able to subdue nature for his own benefit. At the same time, there is a concluding note to the scene that animals are unafraid of human beings. To a great extent, the tractor and the confidence exuded by the man are illusions because the swarming of the natural forces, the birds, are overwhelming and larger in scope and magnitude that humans and technological advances.