Andean Gull

Identification

The Andean gull is one of the larger members of its genus, measuring 42 to 48 cm in length and weighing around 480 g. Adults in breeding plumage are striking and unmistakable: they display a glossy black hood with a distinctive white crescent behind the eye, a mostly white body with gray back, and a white tail. Some individuals show a pink flush on their underparts. The upper wing surface is predominantly gray with an alternating white-black-white-black pattern on the primaries, while the underside of the wing is pale gray with a blackish outer half interrupted by large white "mirrors" on the three outermost primaries. The bill, legs, and feet are blackish brown with a reddish tinge, and the iris is brown. Non-breeding adults are quite different, with a white head and blackish legs. Sexes are alike in plumage. Young birds take two years to attain adult plumage, with first-year birds showing mottled black on the head, complex black and white patterns on the wings, and a black band near the tail's end.

Range & Habitat

The Andean gull is found year-round in the Andes, with its range extending from far southwestern Colombia south through central Ecuador and Peru, western Bolivia, and eastern Chile and western Argentina to approximately the latitude of the north of Chile's Aysén Region. Many individuals migrate to coastal areas during winter, particularly from central Peru southward into northern Chile, though the origin of these wintering birds remains uncertain.

This species inhabits high-altitude environments characteristic of the Altiplano during breeding season, favoring lakes, bogs, marshes, and fields in puna and páramo zones. Elevations typically range from 3,000 to 5,300 m, though in the southern part of its range it descends to as low as 1,200 m. In winter, coastal birds are typically found at river mouths and sand beaches.

Behaviour & Diet

The Andean gull is an opportunistic and versatile forager. In mountain habitats, it feeds on earthworms, insects, amphibians, small fish, and occasionally the eggs and chicks of waterbirds. The species has also been recorded scavenging at ski resorts during winter months. Along the coast, diet shifts to offal, fish, and marine invertebrates. It seeks food by walking, swimming, and flying.

Breeding occurs mostly during July and August. This species is sometimes solitary but more usually nests in small colonies along riverbanks and on islands in rivers and lakes. Clutch size typically consists of two or three eggs, though one or four eggs are sometimes laid. Vocalizations are distinctive and energetic, including "agitated, sometimes tremulous 'yeeer' calls" and "hoarse 'raggh-aggh-keeaagh' and other low raspy notes."

Best Time & Places to See It

The Andean gull is present year-round throughout the Andes, making it accessible to travelers any season. However, breeding birds in their mountain habitat are most abundant during July and August in the puna and páramo zones of the Altiplano, particularly at high-altitude lakes between 3,000 and 5,300 m. Those seeking to observe the species during winter may have better success at coastal locations, particularly at river mouths and sand beaches from central Peru southward into northern Chile. The species has been recorded as a vagrant in Amazonian Peru and far southern Argentina, though such sightings are exceptional.

Photography Tips

The Andean gull's striking breeding plumage—with its glossy black hood contrasting sharply with the white crescent behind the eye and pale body—makes it a rewarding photographic subject during the breeding season. The characteristic pattern on the primaries, visible both from above and below the wing, provides distinctive field marks worth capturing. Non-breeding birds present a different challenge, with their white heads requiring careful exposure management to preserve detail. The species' high-altitude habitat offers dramatic landscape photography opportunities, though the thin air and extreme UV exposure at elevation demand appropriate precautions. Coastal wintering birds at river mouths and beaches may be more approachable for close photography than their mountain-dwelling counterparts.