Facts About the Arctic Skua

Arctic skuas live at sea and come to the ground only for breeding.

Skuas, including Arctic skuas, are a group of seabirds of the Stercorariidae family and the Stercorarius genus. Renowned for their extraordinary speed and agility in the air, Arctic skuas relentlessly chase and harass other birds like guillemots, puffins, and kittiwakes, until they drop the food they are carrying. Hence, they are known as 'avian pirates'.

The scientific name of the Arctic skua is Stercorarius parasiticus, but they are more commonly known as 'Parasitic Skuas' or 'Parasitic Jaegers'. Parasitic Jaeger is the term used for them in North America.

Arctic skuas look quite similar to the Long-tailed Jaeger and the Pomarine skua, and due to this similarity, identifying an Arctic skua can become difficult at times. There are two distinctive forms or color morphs of Arctic skuas - the 'light morph' and the 'dark morph'.

Another intermediate color morph also exists, but it not distinctive, and is usually referred to as the intermediate-phase.

✧ The Arctic skua is a medium-sized seabird that usually reaches a length of 41 to 48 cm, and a wingspan of 107 to 125 cm. The average weight of an adult Arctic skua can be around 450 to 600 grams.

✧ 'Light-morph' Arctic skuas are characterized by a brown back and creamy-white underparts, with some mottling across the belly. The wings are pointed, and have dark feathers with a 'white flash'. This white 'wing flash' is present in other 'color morphs' as well. The neck and head of the 'light-morphs' are usually yellowish-white in color with a black cap.

✧ 'Dark-morph' adult skuas are usually dark brown in color, with a distinct darker cap on their brown plumage. Intermediate color morphs, on the other hand, are dark in color with a pale head and underparts. The neck of these birds is also pale in color.

✧ On the other hand, juveniles of the 'dark morphs' can be distinguished by their chocolate-brown color, and a darker head and neck than the 'light morph' juveniles.

In summer, they can be seen in the coastal moorlands of north and west Scotland, and in the Shetland and Orkney Islands. The tundra in the north Atlantic and north Pacific regions is the main breeding ground of these birds. However, they also breed along the coast, and the moorlands near the sea.

✧ Northern Scotland, Iceland, Norway, Russia, Sweden, and Greenland are the main countries where these birds breed. They reach their breeding ground in early June. When winter approaches, they leave their breeding ground and migrate to the Southern Hemisphere. The migration to the south usually takes place in August.

✧ Some skuas live solely by stealing foods from other birds, which has earned them the name 'avian pirates'. They attack birds like puffins, terns, gulls, and kittiwakes in midair and chase them relentlessly.

The overwhelmed victim finally drops its prey, which is then snapped by the Arctic skua. This feeding behavior is known as 'kleptoparasitism', a term used for stealing food from other species.

✧ However, during the breeding season, Arctic skuas do not make their living solely by kleptoparasitism. They hunt while breeding ashore in the Arctic. They mainly prey on fish, small birds, and mammals.

✧ Arctic skuas come to the shore only in summer for breeding. Sometimes, the young skuas may not come to land after leaving their nest until they reach the breeding age.

✧ Parasitic Jaegers have been observed to display strong nest fidelity by occupying the same territory for several years. Another interesting fact about these birds is that they are monogamous, and they usually pair-up for lifetime, unless death or 'divorce' causes a separation. 'Divorce' can occur if the pair fails to raise any chick in a year.

✧ The incubation period is usually about 26 days. The male Arctic skua also takes part in the incubation process. After hatching, the young ones stay with their parents until they are fledged, which happens at around 5 weeks after hatching. Till then, the parents feed and protect their offspring from potential predators.

✧ Arctic skuas defend their territories strongly in the Arctic regions. But in other places, they form small colonies, which allows breeding birds to defend themselves collectively against predators.

✧ Parasitic Jaegers are often found near the colonies of other seabirds. They are usually silent, except for a nasal mewing sound that they make and repeat a few times when they are on the breeding ground. Sometimes, they also make wailing notes.

The Arctic skua is one of the most abundant skuas in the world. They are often seen flying above the waves or chasing other birds in the pursuit of snatching their food. Like other skuas, Arctic skuas are also related to gulls, auks, waders, and skimmers. In fact, they greatly resemble the stocky gull in appearance.