Just playing with collective nouns...
And a murder flew past my window then,
as a sleuth prowled below, through the trees;
and a raindrop fell,
and a church bell tolled,
and the murder soared high, on the breeze.
Then came a flight of a different kind:
a covert of coots climbed the sky;
and the murder was gone,
and the covert was come,
but the sleuth never saw them pass by.
And the covert flew high, to survey all below,
and it circled a while, and it flew past the trees;
and they sighted a lake of deep-water beneath:
from the sky to the lake, from the wind to the waves,
from dark upon light - to dark upon dark,
from a covert overt - to a covert covert,
they descended, unseen by the sleuth.