Andrew Parkinson / Great skua (Stercorarius skua) territorial adult flying directly toward the photographer in a display of aggression. Shetland Islands, Scotland, UK, June. (non-ex)

Andrew Parkinson / Arctic Skua (Stercorarius parasiticus) in flight, stealing fish from Arctic Tern (Sterna paradisaea). Shetland Islands, Scotland, UK, July. (non-ex)

Andrew Parkinson / Arctic Tern (Sterna paradisaea) in flight chasing Arctic Skua (Stercorarius parasiticus) that has stolen its food. Scotland, UK, July. (non-ex)

Andrew Parkinson / Arctic Skua (Stercorarius parasiticus) pair stealing fish from Arctic Tern (Sterna paradisaea) Shetland Islands, Scotland, UK, July. (non-ex)

Andrew Parkinson / Arctic Skua (Stercorarius parasiticus) pair stealing fish from Arctic Tern (Sterna paradisaea) in flight, Shetland Islands, Scotland, UK, July. (non-ex)

Andrew Parkinson / Arctic Skua (Stercorarius parasiticus) pair almost colliding in flight, as they pursue an Arctic Tern (Sterna paradisaea). Shetland Islands, Scotland, UK, July. (non-ex)

Andrew Parkinson / Great skua (Stercorarius skua) attacking a sheep, in an attempt to prevent it wandering too close to its vulnerable chick. Shetland Islands, Scotland, UK, June (non-ex)

Andrew Parkinson / Great skua (Stercorarius skua) bathing in a freshwater pool. Shetland Islands, Scotland, UK, June. (non-ex)

Andrew Parkinson / Pair of Great skuas (Stercorarius skua) on a misty moorland with person walking close to their territory. Shetland Islands, Scotland, UK, June. (non-ex)

Andrew Parkinson / Breeding pair of Great skuas (Stercorarius skua) in a territorial display to warn off approaching Skuas, Shetland Islands, Scotland, UK, June. (non-ex)

Andrew Parkinson / Great Skua (Stercorarius skua) territorial adult displaying to other Skuas passing overhead by stretching out its wings and calling. Shetland Islands, Scotland, UK, June. (non-ex)

Wild Wonders of Europe / de la Lez / Arctic skua (Stercorarius parasiticus) portrait, Bjrndalen, Svalbard, Norway, July 2008