A hawk hovers above the Done Edwards Wildlife Refuge in San Jose, CA. From my lowly viewpoint, as a simple ground dweller, the hawk was nearly stationary in the sky. It seemed to have found an air current to provide it with the necessary lift, and thus minimized the effort required to keep it aloft.
The hawk was intently scouting the ground below. While I cannot say for sure, it seemed to be using its high vantage point to hunt for something to eat. Small movements on the ground would attract its attention. Occasionally, it would begin diving down fairly quickly towards the ground towards those movements.