Brown-hooded Gull

It is a medium-sized larid that measures between 35 and 42 centimeters in length and has a wingspan ranging from 95 to 105 centimeters. During the breeding season, adults display a striking dark brown hood covering the entire head, which contrasts beautifully with a prominent, broken white eye-ring. The mantle and upper wings are a delicate pale gray, while the rest of the body, including the neck, underparts, and tail, is pristine white. The outer primary feathers feature a diagnostic pattern of white patches with black tips. Its bill, legs, and webbed feet are a deep, dark crimson red. In non-breeding plumage, the dark hood is completely lost, leaving only a small, dusky auricular spot behind the eye, and the bare parts lose their intense coloration, turning to a duller reddish-brown.

Geographical distribution: It is native to the southern cone of South America, with a breeding range extending from central Chile and central Argentina southward to Tierra del Fuego and the Falkland Islands. During the austral winter, southern populations undertake extensive migrations northward along both coasts, reaching northern Chile on the Pacific side, and Uruguay and southeastern Brazil on the Atlantic coast. Vagrant individuals are occasionally reported further north in Peru and as far south as the South Georgia islands.

Habitat: It occupies an exceptionally wide array of coastal, marine, and inland freshwater ecosystems. It is frequently observed along sandy beaches, mudflats, estuaries, and coastal lagoons. In inland regions, it readily adapts to freshwater lakes, rivers, flooded grasslands, and agricultural fields. It is also highly synanthropic, regularly gathering in large numbers around harbors, fish-processing plants, and urban landfills where food is abundant.

Feeding: It is an opportunistic omnivore with a highly varied diet. It feeds on small fish, aquatic invertebrates, mollusks, crustaceans, earthworms, and insects, which it often catches in mid-air. It also scavenges on carrion and organic waste from human activities. Additionally, it frequently exhibits kleptoparasitic behavior, aggressively harassing other waterbirds such as terns and ducks to steal their food.

Behavior: It is a highly gregarious and social bird, typically found in dense flocks that forage, roost, and nest together. Known for its agile flight, it can easily hover and dip to snatch prey from the water´s surface. It is a highly vocal species, uttering sharp, rasping, and cackling calls that intensify during territorial disputes or within breeding colonies. Migration patterns are latitudinal; while northern populations are mostly sedentary, southern high-latitude breeders are fully migratory.

Nesting: It breeds in large, noisy colonies established on the ground near water bodies, often in close proximity to other marsh-nesting birds. The nest is a substantial cup constructed from twigs, dry grasses, and reeds, situated on muddy ground, sandbars, or floating mats of vegetation. Females typically lay 2 to 3 eggs, which are olive-brown and heavily marked with dark spots and blotches. Both sexes share incubation duties for approximately 22 to 24 days and cooperate in feeding and defending the semi-precocial chicks.

Conservation status: It is classified as Least Concern (LC) on the IUCN Red List. The species benefits from an extremely large range and a stable, possibly increasing, global population. Its ability to exploit anthropogenic food sources, such as agricultural waste and garbage dumps, has allowed it to maintain healthy population levels despite regional coastal developments.