To be testified to

To leave lightly on any journey Empty pockets worn shoes These proved (how long ago?) Weightless as nothings nothing at all Even the sharp-caught breath in throat Even a last, wild shake of heart No more empowered to shop short A taking-off timed to occur Than frailty of wing or racing pulse Deters the bird (at a season's close) From letting-go all that it's known Of nest, bough and encompassing scene To proceed -- through vasty provinces of air -- Towards what, already provisioned, awaits The scheduled coming of a feathered thing So small it could couch in a child's hand O to leave is always to launch upon!m And thus done best but those who've shed All that would inter pose a check Before each summons to vault ahead