Vulture and like birds (all birds do this)exploit pockets of rising warm air (thermals) to provide the energy they need for lift. This is why vultures (birds) 'circle', not only to remain in one location over something that might be good to eat, but also to stay within the area of the thermal they are using to gain height.
Snoopy pretends to be a vulture in the comic strip "Peanuts." He is often seen perched on top of his doghouse with his wings spread out, pretending to be a fierce vulture waiting for his prey.
Owls have large wings to improve lift and help in gliding. Speed is a product of thrust or gravity (altitude change). Think evolution gave them large wings so they can glide efficiently to the prey without making noise by flapping their wings.
Sometimes you can hear flapping, but mostly they are just too far away to hear it. Birds of prey tend to glide in when they attack so that their prey cannot hear them flapping and escape.Examples: owls make a soft shushing sound when they fly and mourning doves make a chirping sound that is actually their wings touching together on the down-stroke.
vulture
A hawk can soar upward without flapping its wings by utilizing convection currents, which are upward streams of warm air. As the sun heats the Earth's surface, the warm air rises, creating these currents. By gliding into these rising columns of warm air, the hawk can gain altitude effortlessly, conserving energy while maintaining flight. This technique allows it to travel long distances while searching for prey.
they don't, they are a scavenger
I believe what you saw was the vulture. Now, if they were white marks only near the tips it was the Black Vulture. It also has a black head. It is in most of the east side of the country. If it was silver marks on most of the wingbacks, it was the Turkey Vulture. It has a red head. It is permanent in the east, but it breeds throughout the country and a little into Canada.
Generally, birds of prey do not have a keen sense of smell. The vulture is one that does, and located their prey by smell.
Bald eagle, falcon,vulture
Gyrfalcon, goshawk, gyps vulture.
It's used to rip off the prey's flesh
falcon.