Bat Detecting

I tell him I have a noctule - 25 kHz, whirring
with guttural clunks, gunning through the night.
27 kHz, serotine (quiet, hear the knocking, the
tapping, a slow clock ticking) and 45 kHz, pipistrelle,
pin-wheeling, disappearing, skimming insects from leaves.
I see his face, that slight twitch of jaw. 82 kHz,
greater horseshoe! Torch beam to canopy, his smile,
the pale green light of the dial. 55 kHz, soprano.
It's hard to know where the darkness ends
and he begins, where the bats end and he begins.
45 kHz, pipistrelle - again. I want to raise my arms
to the night, for all the bats to come down,
to be coated with a new kind of skin.