Answer:
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
They can be harbored, but few hold water. You can nurse them, but only by holding them against someone else. You can carry them, but not with your arms. You can bury them, but not in the earth.
What stays on the ground but never gets dirty?
You saw me where I never was and where I could not be. And yet within that very place, my face you often see.
You can only have it once you have given it.
Pirates put their booty in it.