why do vultures fly super high in a circle above the carcasses they find?
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Apparently, that behaviour is not related to feeding.
They are “kettling,” using thermals to save energy in flight.
That’s why they seem to circle – they are riding the rising air currents to gain height.
But it usually has little to do with what’s on the ground.
Vultures are optimized to save energy by soaring in thermal updrafts. Thermals are usually columnar, meaning the vulture must fly in a circle to stay within rising air. Only after the vulture sees a potential meal and assess that it is safe to land and feed does it exit a thermal, descend, and land for its meal.
This article [http://www.birdfellow.com/journal/2012/04/03/flight_styles_thermalling](http://www.birdfellow.com/journal/2012/04/03/flight_styles_thermalling) seems to explain it really well, and has even an illustration on how that works.
Hot air is less dense than cold air, and rises. This is the same principle of hot air balloons.
When the ground is heated, it forms like a upward whirlwind, from the hot air going up and cool air going down.
Vultures and other birds may use this upward wind to stay “afloat” in the air without effort.
Most of the time they are just using a thermal updraft to gain height without using any energy. The thermal updrafts from solar heating tends to form into large funnels. We can not usually see these but the birds can feel them and will circle inside the funnel to soar higher allowing them to glide for long distances.
That is not to say that vultures and other birds do not circle around dead animals. This might be to scout the area for other predators as the birds are very vulnerable when on the ground. If a predator is already on the carcass they might stay flying while they wait their turn or at least until they find a vantage point where they can land.
And then when the vultures are done eating, or get chased away from the carcass, they usually want to fly far away and will search for nearby thermal updrafts. So you might see this circling behaviour after the vultures are done eating.
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