Owl feather. Coloured Scanning Electron Micro- graph (SEM) of a feather from a long-eared owl, Asio otus. The branched hairs of the owl's feathers disrupt turbulent vortices in the airflow over the bird's wings. This helps to make the owl's flight silent so that its prey does not hear it. The shaft of the feather is at bottom. Magnification: x40 at 6x6cm size.