darning needles or ballerinas?

And I chose to swim down the French Broad River
yesterday, following the inner tubes and fun-yaks
flowing with my head upstream, feet up
moving with the water
bumping over rocks and pushing off
down tiny waterfalls
the rocks were softly carpeted with
aquatic grasses, a cushion
and the darning needles, the little dragonflies, perched
on the emerging green rocks, fuzzy islands,
hundreds on their little mat just above the waves
with about a fifth of them
balancing their slender tails on the
heads of their neighbors, wings outstretched
a balancing feat
worthy of the New York City ballet