Q From Lynne Spear: I’ve come across an interesting suggestion for the origins of the idiom as the crow flies. It’s said that the phrase has its roots in something called raven flocking, a method that medieval sailors used to find land. They supposedly kept a raven or a crow on board ship and when the sailors thought they might be near land, they would let the bird loose and would assume land was in the direction in which it flew. Is this true?
A It’s amazing how people can make a simple topic complicated in the search for a good story.
I’ve not come across raven flocking and can’t find a reference to it anywhere. So far as I know, adult ravens don’t flock: they mate for life and defend a territory. British crows don’t flock either, though American crows and the closely similar European rooks do, the latter being gregarious birds that nest in colonies.
You sent me a link your husband found to a website of sailing trivia. It explains the expression in a related way:
The term As The Crow Flies came from British coastal vessels that customarily carried a cage of crows. Crows detest large expanses of water and head, as straight as a crow flies, towards the nearest land if released at sea — very useful if you were unsure of the nearest land when sailing in foggy waters before the days of radar. The lookout perch on sailing vessels thus became known as the crow’s nest.
I’d hate to see a cage of crows: the birds would probably peck each other to death. And the birds must have had supernatural powers, to be able unerringly to see land through fog. You can tell this is folk etymology through its linking of the story to the crow’s nest, which has no etymological connection with as the crow flies. The crow’s nest was given that name because, like the nest of a crow in a tree, it was perched high on the mast as a lookout point. It was invented only at the end of the eighteenth century by Captain William Scoresby of Whitby, a captain in the Greenland whale fishery, and wasn't used by coastal vessels.
The expression can’t be from medieval times, because it’s recorded only from the eighteenth century. And all early instances refer to directions on land with no mention of the sea, as does the French equivalent, à vol d’oiseau, which doesn’t refer to a specific bird. However, the two stories may reflect some ancient sailing practice. One is biblical: those who know the book of Genesis (Chapter 8, Verses 7-8) will recall that at the end of the flood Noah sent out a dove to test for dry land. It’s less well known that he first sent out a raven. Scholars have suggested that using birds in this way was common. The Vikings are believed to have released ravens to point them towards land because they fly high and can see further. This is known from the saga of Floki, also called Ravna-Floki (Raven-Floki), because he took three ravens with him in his journey from Shetland to search for Iceland. (Might your source have converted Raven-Floki by folk etymology into raven flocking?)
However, the two folk tales above remain etymologically false because neither gives the real story of the idiom. The true explanation lies in British country lore that’s based on observation of the birds. Anyone who has watched a crow flying any distance knows it tends to do so in a steady, unwavering line — not always, but then this is a generalisation of a tendency, not invariable fact. Since the flight of the crow is unaffected by obstacles on the ground, its route came to represent the shortest distance between two points.
This is the earliest example I’ve so far found:
Now the country that those Indians inhabit is upwards of 400 miles broad, and above 600 long, each as the crow flies.
The Gentleman’s and London Magazine, Dec. 1761.
And this slightly later one makes the link explicit:
The Spaniard, 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, and by this means shortens his journey so considerably, that he can carry an express with greater expedition than any horseman.
The Political Magazine, Nov. 1782.
Another expression from the natural world has a related sense: to make a bee-line for something means to take the shortest and quickest route towards an objective. This comes from another old country belief, that bees returning to the hive after gathering nectar always do so in a straight line. This has been disproved.