Mostly they choose reasonably tall trees, 10 – 55 metres above the ground. The nest is usually below the canopy of the tree on the main stem where there are good supporting branches. They prefer to have a certain amount of trees around the nest tree screening them from both the weather and prying eyes.
Of course, as with all living creatures, there are exceptions to the rule. In the picture below this nest was at only 3.5 metres above the ground!