The turkey vultures of Columbia, Missouri, have established a large colonial roost near the south edge of the MU campus. From our back deck, a mile northwest of the roost, I often see these graceful birds heading east during the hour before sunset, as they return to that site.
Like commercial jets on final approach, the vultures seem to follow a rather strict flight path and those arriving from the north or south merge into the same inbound lane. Since this scenario is not observed every evening, I must assume that their route of descent, like plane traffic, is determined by the wind direction. Though I have no direct evidence, I suspect that, given their highly developed sense of smell, the vultures are guided by the odor of their roost, carried on the wind; if that is the case, then they, like aircraft, land into the wind, an approach that yields more control from an aerodynamic point of view.
While the above musings may be off target, it is by simple observation that scientific theories are spawned; if found to be valid through more rigorous testing, our understanding of the natural world is advanced. At the very least, attention to the habits and behavior of our wild neighbors is an enjoyable and educational exercise.