Swallows, swifts and martins

Swallows, swifts and martins fly;
like a feathery, lightning flash, go by
in the blink of an old birdwatchers eye,
across the broad, blue summer sky.

A glimpse of wing and a two pronged tail
is all my eye, slow as a snail,
of these bright birds, can ever see
for they fly far, far too fast for me.