What birds have the slowest wing-beats?

Answer 1

Birds with longer wingspans do not have to beat their wings as fast. It's the same as the difference between a jet fighter and an unpowered glider aircraft: the jet needs a lot of thrust to allow its smaller wings to produce the same amount of lift, whereas the glider has a large wingspan and flies at slower speeds. As an example, egrets, cranes, swans, and herons all have long wingspans and beat their wings slower than smaller birds. However, birds that soar long distances sometimes can travel for hundreds of miles without flapping their wings. Hawks, vultures, and eagles riding thermals can travel long distances without flapping their wings, and seabirds such as gulls, frigatebirds, and albatross are masters of efficient flight and can travel for very long periods without flapping their wings or landing at all.