Why do buzzards circle around their prey in the sky?

They are actually not circling waiting for something to die. They are waiting in a thermal, which is the most energy-efficient way to fly, to pick up the scent of something that is already dead (buzzards and vultures are one of the few types of birds that have a sense of smell). read more

Contrary to conventional folklore, buzzards and vultures like their food as fresh as they can get it. They feed mostly on carrion, but since they are opportunistic eaters, they will sometimes kill injured or helpless prey. read more

To ‘hide’ from their prey, buzzards fly high up into the sky. They will often be seen circling because they are using thermals of rising air that slowly spiral upwards. The bird can spot moving prey from up to 1 mile away, that good is its vision. read more

Vultures will also circle over a kill made by a much larger predator, like a lion or a leopard. The large predators don't like to share their kill and will attack vultures if they get too close (though they rarely eat vultures), so the scavenger birds circle the kill and wait for their chance. read more