The Parasitic Jaeger (Stercorarius parasiticus) is a sleek, falcon-like seabird that lives as an aerial pirate, chasing terns and small gulls in breathtaking pursuits until they drop their catch, which the jaeger then snatches from the air. It measures 41–48 cm long with a wingspan of roughly 108–125 cm and weighs about 330–570 grams, occurring in two colour forms: a dark, more or less uniformly brown morph, and a pale morph with a dark cap, white underparts, and a yellowish wash on the neck sides. Adults show pointed, somewhat protruding central tail feathers around 3–8 cm long, and the flight is buoyant, fast, and elegant — almost falcon-like.
At the breeding site it gives whining, mewing calls, often described as a plaintive "me-a", though it is largely silent outside the breeding season. In Sweden it breeds in small numbers in the northern archipelagos along the Gulf of Bothnia and at mountain tarns in the far north — the Swedish population is small, on the order of a few hundred to around a thousand pairs — while during spring and autumn migration birds pass along the coasts and are seen regularly at watch points. The nest is a simple scrape on the ground, often on a tussock, with two eggs incubated by both parents for about 25–28 days; pairs defend the nest aggressively, even against approaching humans. It is a specialist kleptoparasite, stealing fish from terns and small gulls in flight, while at mountain tarns it also takes small rodents, insects, eggs, and chicks, and catches fish itself out at sea, where it winters in tropical and subtropical waters.
Read about this species in Swedish →