Read the passage.

To Waken an Old Lady

by William Carlos Williams

Old age is
a flight of small
cheeping birds
skimming
bare trees
above a snow glaze.
Gaining and failing
they are buffeted
by a dark wind—
But what?
On harsh weedstalks
the flock has rested,
the snow
is covered with broken
seedhusks
and the wind tempered
by a shrill
piping of plenty.

What do the small cheeping birds symbolize in this poem?