[8][9] The genus name Stercorarius is Latin and means "of dung"; the food disgorged by other birds when pursued by skuas was once thought to be excrement.

The herring gull size, massive barrel chest and white wing flashes of this bird are distinctive even at a distance.

They are a migrant species, wintering at sea in the Atlantic Ocean and regularly reaching North American waters.

A common technique is to fly up to a gannet in mid-air and grab it by the wing, so that it stalls and falls into the sea, where the great skua then physically attacks it until it surrenders its catch.

Due to its size, aggressive nature and fierce defence of its nest, the great skua has little to fear from other predators.

An aerial apex predator, the great skua is an also an aggressive kleptoparasite, deliberately harassing birds as large as gannets to steal a free meal.

Great skuas show little to no fear of humans – anybody getting close to the nest will be repeatedly dive-bombed by the territorial adults.

Unusual behaviour by St Kilda's skuas was recorded in 2007 during research into recent falls in the Leach's storm petrel population.