Why doesn't a soul fly when it hears the call?

Why doesn't a soul fly when it hears the call? Fish on the beach always move towards wave-sound.-Rumi

You have escaped the cage.
Your wings are stretched out. Now FLY.
You have slept in sheds and outbuildings so long you think you live there.-Rumi

Don't you know yet?
Fling the emptiness out of your arms into the spaces we breathe-
maybe that the birds will feel the extended air in more intimate flight.-Rilke