A poem often requested

This poem, from Memories in Clay, Dreams of Wolves, is often requested when I do a public reading:

from the inertia of the flight               transferred from sky to silent tree                            this time, the rock flew certain,   the arm was true, the motion perfect.               There was a "thuk"–as if the rock                         had struck the branch alone.   The robin stumbled from the tree,               dropping feathers, losing its flight,                         abandoning its grace, its pulse of life.   The robin bounced three inches               from the red clay bared by a shovel                         beneath the silent locust tree.   The bird lay still. The tree no               longer moved. The boy stood, stunned                         by the anger of his unthought aim,   by the power of his arm to negate               the flight, the pulse of bird.                         There was no blood. The robin's eyes   were beady, but clear. The boy               backed away from the black feathers.                         The rock had disappeared,   transferring its stillness, its inertia               of silence and negation                         to deny the pulse, the life of bird.   The bird lay still, its eyes useless,               its wings folded against its breast,                         having spent its motion to the stone.
The rock flew on with the bird's               momentum–forever–in the boy's mind                           negating the wind, the sky, the just passed spring.