Mergus octosetaceus
The Brazilian Merganser (Mergus octosetaceus) is a critically endangered waterfowl species, a true gem of South American rivers. This medium-sized duck measures approximately 49-56 cm (19-22 inches) in length, with a long, slender body and an average weight of 600-700 grams. Males and females share a striking appearance, though males can be slightly larger; both feature a glossy dark green head, often appearing black, topped with a distinctive shaggy crest that falls gracefully over the nape....
This highly specialized merganser exclusively inhabits pristine, fast-flowing rivers and streams with clear, oxygenated water, often featuring rocky substrates, rapids, and dense riparian forest cover. It thrives in areas with abundant submerged vegetation and suitable rock crevices or tree hollo...
The diet of the Brazilian Merganser consists almost exclusively of small freshwater fish, which they efficiently capture by diving and pursuing them underwater. They also occasionally consume insect larvae and small crustaceans.
Brazilian Mergansers are diurnal, spending their days actively foraging or resting on exposed rocks and sandbanks within their riverine territories. They are highly skilled dive-fishers, using their streamlined bodies and powerful legs to pursue and capture fish underwater, often staying submerge...
The Brazilian Merganser historically had a wider, albeit still restricted, distribution across central and southern Brazil, eastern Paraguay, and northeastern Argentina. Today, its range is highly fragmented and critically reduced, with known populations primarily confined to specific, isolated r...
Critically Endangered
- It is one of the most endangered waterfowl species globally, with fewer than 250 individuals estimated to remain in the wild. - The Brazilian Merganser is the only species of merganser found in the Southern Hemisphere, making it geographically unique among its relatives. - Its extremely narrow,...