“When measured as the crow flies” is an idiomatic expression used to describe the shortest distance between two points, typically measured in a straight line, without taking into account any obstacles or the actual path that would be followed. It implies a direct route between two locations, as if a crow were to fly directly from one point to another, disregarding any physical barriers such as mountains, rivers, buildings, or roads.
For example, if someone says that two places are “2 miles as the crow flies,” it means that the straight-line distance between those places is approximately 2 miles. However, the actual distance traveled by a person or vehicle may be longer due to the need to navigate around obstacles and follow the existing roads or pathways.