Lucky, because flying birds need a lot of oxygen even when they fly at high altitudes where the atmosphere is thin. One big difference is in how they fly. Herons pull their neck into a crook while they fly, while cranes fly with their neck outstretched. Their wings help them to accomplish all of these jobs. Getting up in the air Whooping Cranes taking off.
Birds have many different ways of taking off.
Some, like loons, run into the wind, and the rush of air beneath their wings lifts them up. Some, like puffins and Peregrine Falcons, jump off cliffs and other high perches. Chimney Swifts simply let go of their chimney or other vertical perch, and fall into the air. Hummingbird wingbeats are so powerful that they can go straight up from a perched position without jumping. Songbirds, cranes, and many other species leap up on strong legs while flapping their wings, and there they go.