Abstract
As we look about us, the world is one
gigantic flight cage. All known forms of
life are confined to a very small area in
comparison to the size of the known universe.
But if we compare the surface area
of the earth to the number of animals
inhabiting the earth, it might seem scarcely
populated. The significant point is that
species evolved in an environment that
would support a certain density or number
of birds within a given area.....