"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.