Chilean Skua

Distinguished by its robust build and predatory habits, this large and powerful seabird measures between 53 and 58 centimeters in length, boasts a wingspan of 130 to 138 centimeters, and weighs between 1.1 and 1.7 kilograms. It features dark brown upperparts that contrast sharply with its warm cinnamon-rufous underparts and underwing coverts. In flight, prominent white patches at the base of the primary feathers serve as a key diagnostic field mark. The bill is heavy and sharply hooked, with a bluish-gray base and a black tip, complemented by dark, webbed feet equipped with sharp claws.

Geographical distribution: Breeds extensively in the southern regions of South America, including the fjords and coasts of southern Chile, the Argentine Patagonia, and the archipelagos of Tierra del Fuego. During the austral winter, it migrates northward along oceanic currents, regularly reaching the coastal waters of Peru in the Pacific and southern Brazil in the Atlantic.

Habitat: Primarily inhabits temperate and subantarctic marine and coastal zones. During the breeding season, it selects rocky islands, coastal grassy cliffs, and headlands near large colonies of other seabirds. In the non-breeding season, it exhibits pelagic tendencies, foraging over continental shelf waters, semi-enclosed bays, and coastal estuaries.

Feeding: Functions as an opportunistic predator, scavenger, and highly skilled kleptoparasite. Its diet consists of fish, marine invertebrates, eggs, and chicks of penguins and cormorants, as well as carrion. It is famous for aggressively harassing gulls, terns, and boobies in mid-air, forcing them to disgorge their prey, which it then swiftly catches. It also frequently follows fishing vessels to feed on discarded offal.

Behavior: Renowned for its powerful, direct flight with steady wingbeats, capable of sudden bursts of speed and agile aerial maneuvers. During the breeding season, it is highly territorial and forms monogamous pairs. It defends its nesting territory with extreme boldness, executing aggressive dive-bombing runs and emitting harsh, cackling alarm calls against intruders, including humans. Outside of the breeding period, it is mostly solitary but may gather in loose groups around concentrated food sources.

Nesting: The breeding season commences around October or November. It establishes loose nesting colonies on open, grassy slopes or flat coastal plains. The nest is a shallow scrape on the ground, sparsely lined with local grasses and lichens. A typical clutch consists of 1 to 2 eggs, which are olive-brown and heavily blotched with dark markings. Both parents share incubation duties for approximately 29 to 32 days and actively protect the semi-precocial chicks, which fledge and become independent after about 6 to 7 weeks.

Conservation status: Listed as Least Concern (LC) on the IUCN Red List. Although the global population is currently considered stable, localized threats exist, including habitat degradation caused by introduced mammalian predators, plastic pollution, oil spills, and potential accidental mortality associated with commercial longline fisheries.