I was watching a robin fly after a finch—the smaller 
chirping with excitement, the bigger, its breast blazing, silent
in light-winged earnest chase—when, out of nowhere
over the chimneys and the shivering front gardens,
flashes a sparrowhawk headlong, a light brown burn
scorching the air from which it simply plucks
like a ripe fruit the stopped robin, whose two or three
cheeps of terminal surprise twinkle in the silence
closing over the empty street when the birds have gone
about their business, and I began to understand
how a poem can happen: you have your eye on a small
elusive detail, pursuing its music, when a terrible truth
strikes and your heart cries out, being carried off.