The phrase as the crow flies refers to the shortest distance between two points. But here’s something else you may not know about crows. British coastal vessels used to carry a cage of crows with them in the days before radar (this is also why the lookout perch on sailing vessels is known as the crow’s nest). When released while at sea, crows fly towards the nearest land which was particularly useful back in the day if the ship’s captain was sailing in foggy waters and was unsure as to where land lay. The reason crows fly towards the nearest land is because crows detest large expanses of water.
It wasn’t until 1934 that a patent was granted in the United States to Taylor, Young and Hyland for a system for detecting objects by radio and further interest in radar development was shown in America by the Naval Research Laboratory, US Army Signal Corps, RCA and AT&T Bell Laboratories. Research and development continued throughout the 1930s in countries around the world.
In The Living Age magazine, in Volume 0164, Issue 2121 published on February 14, 1885, the magazine contained a story that said:
Towards evening, they sky above the mountains opposite to my place of observation yielded a series of the most splendidly-coloured iris-rings; but on lowering the selenite until it had the darkness of the pines at the opposite side of the Rhone valley, instead of the darkness of space as a background, t he colours were not much diminished in brilliancy. I should estimate the distance across the valley, as the crow flies, to the opposite mountains, at nine miles; so that a body of air nine miles thick can, under favourable circumstances, produce chromatic effects of polarization almost as vivid as those produced by the sky itself.
Over a century before that, the London Review Of English And Foreign Liturature, by W. Kenrick published in 1767 provides this passage:
The Spaniaad [sic], if on foot, always travels as the crow flies, which the openness and dryness of the country permits; neither rivers nor the steepest mountains stop his course, he swims over the one and scales the other.
In 1540, Garci Lopez de Cardenas led a party to the Grand Canyon. Pedro de Castaneda Najera recorded the event and said that the Spaniards estimated the width of the canyon to the north to be:
… three or four leagues as the crow flies across to the other bank of the stream which flowed between [the rims].
In the accounts of Sultan Mahmud‘s Kanauj campaign of AD 1018, there are multiple references to “as the crow flies” when stating distances. And 1st-century Romano-Jewish historian and hagiographer, Josephus (37 AD – 100 AD) used the term “as the crow flies” when stating distances. For example, the distance from Jerusalem to the Mount of Olives was six furlongs (3,637 feet) but only five furlongs (3,031 feet) as the crow flies.
As a side note, the most important works by Josephus were The Jewish War written around 75 AD that dealt with the Jewish revolt against Roman occupation and Antiquities of the Jews written around 94 AD that dealt with the history of the world from a Jewish perspective.
It is very likely that the phrase “as the crow flies” goes back even further however Idiomation was unable to find any records going back beyond this date for this particular phrase.
Historically Speaking 