The expression as the crow flies is an idiom for the most direct path between two points. [1] [2]
The meaning of the expression is attested from the early 19th century, and appeared in the Charles Dickens novel Oliver Twist (1838): [1] [2]
"We cut over the fields at the back with him between us – straight as the crow flies – through hedge and ditch." [1]
Crows do conspicuously fly alone across open country, but crows do not fly in particularly straight lines. [3] While crows do not swoop in the air like swallows or starlings, they often circle above their nests. [3]
One suggested origin of the term is that before modern navigational methods were introduced, cages of crows were kept upon ships and a bird would be released from the crow's nest when required to assist navigation, in the hope that it would fly directly towards land. [1] However, the earliest recorded uses of the term are not nautical in nature, and the crow's nest of a ship is thought to derive from its shape and position rather than its use as a platform for releasing crows. [1] It has also been suggested that crows would not travel well in cages, as they fight if confined. [4]
as the crow flies.