The Knife
"Variation of Birds"

Scissor-beak lower mandible flat elastic
its an ivory paper-cutter
lower mandible immersed some depth in the water
it flies rapidly up and down the stream.

So that there are three sorts of birds which use their wings
for more purposes than flying
the steamer as paddles the penguin as fins
and the ostrich spreads its plumes like sails to the breeze.