Arctic Skua
Facts
Also known as: Parasitic Jaeger, Parasitic Skua
Conservation Status: Least Concern
Location: North Eurasia and North America
Lifespan: About 11 years
Also known as: Parasitic Jaeger, Parasitic Skua
Conservation Status: Least Concern
Location: North Eurasia and North America
Lifespan: About 11 years
Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Stercorariidae
Genus: Stercorarius
Species: S. parasiticus
Binomial name: Stercorarius parasiticus
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Stercorariidae
Genus: Stercorarius
Species: S. parasiticus
Binomial name: Stercorarius parasiticus
Description
Length: Average 41 cm (16 in)
Other: Light phase adults have a brown back, mainly white underparts and dark primary wing feathers with a white "flash". The head and neck are yellowish-white with a black cap and there is a pointed central tail projection. Dark phase adults are dark brown, and intermediate phase birds are dark with somewhat paler underparts, head and neck. All phases have the white wing flash. Juveniles are even more problematic, and are difficult to separate from Long-tailed Skua over the sea. They are bulkier, shorter-winged and less tern-like than that species, but show the same wide range of plumage variation. The flight is more falcon-like. However, they are usually warmer toned than Long-tailed, with browner shades, rather than grey.
Length: Average 41 cm (16 in)
Other: Light phase adults have a brown back, mainly white underparts and dark primary wing feathers with a white "flash". The head and neck are yellowish-white with a black cap and there is a pointed central tail projection. Dark phase adults are dark brown, and intermediate phase birds are dark with somewhat paler underparts, head and neck. All phases have the white wing flash. Juveniles are even more problematic, and are difficult to separate from Long-tailed Skua over the sea. They are bulkier, shorter-winged and less tern-like than that species, but show the same wide range of plumage variation. The flight is more falcon-like. However, they are usually warmer toned than Long-tailed, with browner shades, rather than grey.
Behaviour
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 or fox approaching its nest. Although it cannot inflict serious damage, it is a frightening and painful experience. It is a migrant, wintering at sea in the tropics and southern oceans.
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 or fox approaching its nest. Although it cannot inflict serious damage, it is a frightening and painful experience. It is a migrant, wintering at sea in the tropics and southern oceans.
Predators or prey?
Some scientists believe decreases in skua populations on some islands may be due to declines in burrowing petrel numbers (a key prey species) from predation by introduced cats. Although, this species has no immediate predators. The Arctic Skua will prey on rodents, birds, and insects. The species also steals others birds catches of food. These other birds include gulls and terns. Like most other skua species, it continues this piratical behaviour throughout the year, showing less agility and more brute force than the smaller skuas when it harasses its victims. 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.
Some scientists believe decreases in skua populations on some islands may be due to declines in burrowing petrel numbers (a key prey species) from predation by introduced cats. Although, this species has no immediate predators. The Arctic Skua will prey on rodents, birds, and insects. The species also steals others birds catches of food. These other birds include gulls and terns. Like most other skua species, it continues this piratical behaviour throughout the year, showing less agility and more brute force than the smaller skuas when it harasses its victims. 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.
Diet
This bird will feed on rodents, small birds and insects. This bird eats mainly fish, which it often obtains by robbing gulls, terns and even Northern Gannets of their catches. It will also directly attack and kill other seabirds, up to the size of Great Black-backed Gulls.
This bird will feed on rodents, small birds and insects. This bird eats mainly fish, which it often obtains by robbing gulls, terns and even Northern Gannets of their catches. It will also directly attack and kill other seabirds, up to the size of Great Black-backed Gulls.
Habitat
In summer it is most easily seen in the Shetland and Orkney islands, and on some coastal moorlands of north and west Scotland; on passage best looked for from coasts in August and September, especially in areas near tern colonies where there are good numbers of feeding terns.
In summer it is most easily seen in the Shetland and Orkney islands, and on some coastal moorlands of north and west Scotland; on passage best looked for from coasts in August and September, especially in areas near tern colonies where there are good numbers of feeding terns.
Conservation
Arctic skua is currently identified as a conservation priority in the following: Red listed in Birds of Conservation Concern 3 (2009 update)
Arctic skua is currently identified as a conservation priority in the following: Red listed in Birds of Conservation Concern 3 (2009 update)
Reproduction
It breeds on coastal moorland and rocky islands, usually laying two spotted olive-brown eggs in grass-lined nests. Like other skuas, it will fly at the head of a human or other intruder approaching its nest. Although it cannot inflict serious damage, such an experience with a bird of this size is frightening.
It breeds on coastal moorland and rocky islands, usually laying two spotted olive-brown eggs in grass-lined nests. Like other skuas, it will fly at the head of a human or other intruder approaching its nest. Although it cannot inflict serious damage, such an experience with a bird of this size is frightening.