Black-collared Hawk

Distinguished by its vibrant plumage and specialized physical adaptations, this medium-to-large raptor, scientifically classified as Busarellus nigricollis, reaches a body length of 46 to 53 centimeters and a wingspan ranging from 115 to 135 centimeters. The body is cloaked in a rich, bright rufous-cinnamon color, contrasted by a pale, almost whitish head with fine dark shaft-streaks. A prominent black collar or crescent-shaped patch adorns the upper breast, giving the species its common English name. Its broad, rounded wings display black flight feathers, and the short tail is blackish at the base with rufous-cinnamon bands and a white tip. The eyes are reddish-brown, the heavy, hooked bill is black, and the long legs are pale bluish-gray or whitish. Crucially, the soles of its feet are covered in rough spicules, a specialized anatomical adaptation designed to grasp slippery, wet aquatic prey.

Geographical distribution: This bird is widely distributed across the Neotropical region, ranging from the lowlands of Mexico (along both the Pacific and Gulf coasts) through Central America and deep into South America. Its range extends to northern Argentina, Paraguay, Bolivia, and throughout the vast Amazon Basin of Brazil. It is predominantly a sedentary species, rarely found at elevations exceeding 500 meters above sea level, staying close to stable aquatic basins year-round.

Habitat: Strongly tied to lowland aquatic ecosystems, this species is frequently observed in marshes, mangrove swamps, slow-flowing riverbanks, permanent freshwater lakes, and seasonally flooded grasslands such as the Pantanal and the Llanos. It also utilizes man-made wetlands and flooded rice fields. Adequate habitat must feature tall, sturdy trees, dead snags, or high perches immediately adjacent to open water, which serve as essential hunting platforms.

Feeding: It is highly specialized as a piscivore, with small to medium-sized fish making up the bulk of its diet. From its high, exposed perch, the hawk scans the water´s surface, launching a low-glide swoop once a target is spotted. It snatches the fish from the water using only its feet, rarely submerging its body. To supplement its diet, it also opportunistically preys on amphibians, aquatic snails, crabs, small lizards, and large aquatic insects, adjusting its foraging habits based on the seasonal water levels of its wetland habitat.

Behavior: It exhibits solitary tendencies, though it is often seen in stable, territorial pairs. It spends much of the day perching upright on prominent branches overlooking water bodies, remaining motionless for extended periods. Its flight style is heavy and slow, marked by deliberate wingbeats and short glides between perches. When disturbed or establishing territory, it utters a distinctive, rasping, guttural call, often described as a harsh, low-pitched croak or crow-like sound.

Nesting: The breeding season varies by region, typically aligning with the onset of local rainy seasons. The pair constructs a bulky stick nest in the fork of a mature tree, often 10 to 25 meters above the ground, sometimes directly overhanging the water. The nest bowl is lined with fresh green leaves to maintain humidity. The female lays a clutch of 1 to 2 eggs, which are off-white or yellowish-white, heavily blotched with reddish-brown spots. Both parents share incubation duties, lasting approximately 35 to 40 days, and cooperatively provision the nestlings until they fledge.

Conservation status: It is currently listed as Least Concern (LC) on the IUCN Red List, owing to its vast geographical range and stable global population. However, localized populations are increasingly threatened by the drainage of wetlands, logging of gallery forests, water pollution from agricultural runoff, and heavy metal contamination, particularly mercury bioaccumulation from gold mining activities in river basins.