The Arctic Skua or Parasitic Skua, (Stercorarius parasiticus) is the most common and regular breeding species in the circumpolar Arctic of the skua family Stercorariidae, It nests on dry tundra, higher fells and islands, laying up to four olive-brown eggs. It is usually silent except for newing and wailing notes while on the breeding grounds. Like other skuas, it will fly at the head of a human, fox or other intrudors approaching its nest. It is a migrant, wintering at sea in the tropics and southern oceans. Arctic skuas feed on rodents, small birds and insects but also robs gulls and terns of their catches. Like the larger skua species, it continues this piratical behaviour throughout the year, showing great agility as it harasses its victims.