That is impressive for a vigesimal size bird to do that.  Did u know that the largest Albatross dose that trip too.  But remained in flight up to seven years with out landing.  They have the best gliding ratio of all birds, 22:1 to 23:1.  They will drop 1 meter at a distance of 22 to 23 meter.  there wing-body ratio is 2:1, wing twice as long as there body.
Do you know how birds, like these two, can fly for a long time with out falling asleep?