"As the crow
flies" is itself becoming archaic
, but it has a companion
phrase that is even less-frequently heard. "As the fox runs
" refers to the distance that a terrestrial
creature would have to travel to reach a certain destination
How far must I travel from here to reach the shire?
It's but a short distance as the crow flies. But between us lies the forest of peril, treachery, and GTKY nodes, so it will be a journey of several days as the fox runs.
Sometimes the fox is replaced with a deer
or a wolf