Updrafts are found when a wind blowing at a hill or mountain has to rise to climb over it. Updrafts can also be found over dark land masses that absorb more heat from the sun than light land masses. The heat from the ground heats the surrounding air, which causes the air to rise. The rising pockets of hot air are called thermals . Large gliding birds, such as owls and hawks, are often seen circling inside a thermal to gain altitude without flapping their wings.
Gliders can do exactly the same thing.