Birds seem to have a natural affinity for high vantage points, including power wires, the tops of trees, and the sides and tops of buildings.
However I presume the top of the Burj Khalifa is not packed with birds, flyover video of cities full of skyscrapers suggest this would not be the case.
Q: Therefore, is there a cap, if so at what height, where higher is no longer better? Perhaps the birds vantage point is reduced by going higher.
Related, but I feel different: Why do crows sit on treetops even when it is cold?