The great skua is an aggressive pirate of the seas, deliberately harassing birds as large as gannets to steal a free meal. It also readily kills and eats smaller birds such as puffins.
Great skuas show little fear of humans - anybody getting close to the nest will be repeatedly dive-bombed by the angry adult. These birds migrate to the northernmost isles of the UK from their wintering grounds off the coasts of Spain and Africa. At a distance they look stout and dark and show white wing flashes in flight.