The only clear thing is that we humans are the only species with the power to destroy the earth as we know it. The birds have no such power, nor do the insects, nor does any mammal. Yet if we have the capacity to destroy the earth, so, too, do we have the capacity to protect it.
You may call a jay a bird. Well, so he is, in a measure--because he's got feathers on him, and don't belong to no church, perhaps;but otherwise he is just as much a human as you be. And I'll tell you for why. A jay's gifts and instincts, and feelings, and interests, cover the whole ground. A jay hasn't got any more principle than a Congressman.
When you have shot one bird flying you have shot all birds flying. They are all different and they fly in different ways but the sensation is the same and the last one is as good as the first.
I have read in books that we are called 'caged birds'. I cannot speak for others, but I had so much in this cage of mine that there was not room for it in the universe- at least that is what I then felt.