Brown Skua: where and when to see them

The brown skua is a robust predatory seabird of southern oceans and subantarctic islands, reaching the Antarctic Peninsula region. Its dark plumage and powerful bill suit an adaptable scavenger and hunter around seabird colonies. The name covers geographically differentiated forms whose treatment has varied between taxonomic authorities. It overlaps with the south polar skua in parts of the Antarctic region, where hybridization can make identification more complicated than a simple comparison of colour.

Size

50-64 cm long

Weight

1.2-2.2 kg

Lifespan

Not reliably established

Status

Least Concern

Brown skuas patrol colonies, shorelines and coastal waters, taking unattended food and sometimes chasing other seabirds until they release a meal. Breeding pairs defend territories forcefully, including areas containing reliable food resources. They nest on open ground and can direct close aerial passes at intruders. Both adults attend the nest and chicks. Outside breeding, movements become more marine, and birds may roam widely rather than remaining near the islands where they nested. Outside of the breeding season, brown skuas disperse widely across the southern oceans, sometimes reaching warmer waters in search of food. They are strong, agile fliers, capable of sustained flight and often seen harassing other birds mid-air to steal their catches.

• Brown and south polar skuas hybridize where their breeding ranges overlap.
• Some pairs defend feeding territories around portions of seabird colonies.
• White patches in the outer wings become conspicuous in flight.
• Skuas obtain food both by hunting and by stealing from other birds.

November through March is the main visitor season for Antarctic Peninsula waters and overlaps the southern breeding period. Brown skuas are more relevant to maritime and subantarctic sites than deep continental locations. Snow conditions, permitted access and overlap with south polar skuas affect observation and identification. Prime viewing opportunities occur when skuas are actively breeding and raising young, as they are more localized and protective of their territories. From the ship, look for them soaring along the coastlines or resting on icebergs, particularly when near known seabird rookeries.

Subantarctic islands and parts of the maritime Antarctic provide breeding habitat, particularly ice-free ground near seabird colonies. Coastal grassland, rocky slopes and open ground are used. At sea, brown skuas occupy southern ocean waters, but they are not characteristic residents of the Antarctic continental interior. They often choose elevated positions on headlands or ridges to provide a good vantage point over their territory and food sources. Their preferred nesting sites are typically located within a few kilometers of the coast, often near penguin or petrel colonies.

Fish, carrion, seabird eggs and chicks are major foods, with proportions varying greatly among territories. Some birds specialize in resources associated with particular colonies. They also steal prey from other seabirds, making both active hunting and opportunistic scavenging important parts of their feeding ecology. They are highly opportunistic predators and scavengers, readily consuming anything from krill and small fish to the eggs and chicks of penguins and other seabirds. During the breeding season, they frequently raid unattended nests, demonstrating a keen sense for vulnerable prey.

Common name

Brown Skua

Scientific name

Stercorarius antarcticus

Animal group

Birds

Size

50-64 cm long

Weight

1.2-2.2 kg

Lifespan

Not reliably established

Status

Least Concern

Identification

Brown skuas are generally bulkier and heavier-billed than south polar skuas, but plumage overlap and hybridization mean some Antarctic-region birds cannot be identified confidently from appearance alone. Key physical traits for distinguishing brown skuas include their overall dark brown plumage, often with a paler nape, and prominent white wing flashes visible in flight. Juveniles tend to be even darker and more uniformly colored, which can make identification challenging.