Strange Black Dog

This morning in the north west wind
which bent the bright green winter wheat
a strange black dog came running, fast.
as fast, as manic as the gale, which blew the grass,
all edged with brown,
and blew the dog, so small and neat,
across the field and up the bank,
one ear turned back and skin side out.
His fur was wet with sweat and dew, his feet,
so dainty, seemed too small.
His bright, sharp eyes were black and keen
pursuing something quite unseen,
chasing an idea, a scent.
His running seemed quite twice the speed,
of any dog I'd seen before.
When all at once he heard a call
and turned around and fleet as fox
retraced his steps across the mud,
until he was a speck once more,
a tiny, crazy thing so small,
and then he was invisible.
And as I gazed, entranced and stood
beside the willows in the wood,
I wondered was he physical,
or had I seen a metaphor.