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Version 1.0

This is a historic version of this account.  Current version


Brazilian Merganser Mergus octosetaceus

Ivana R. Lamas and Líiva V. Lins
Version: 1.0 — Published April 28, 2009


Distinguishing Characteristics

Similar Species

This species is the only representative of the Mergini Tribe (Anatidae, Anseriformes) in the southern hemisphere.
For the layperson, the Brazilian Merganser may recall the Neotropic Cormorant (Phalacrocorax brasilianus), which can occur in the same places as the merganser. But it is not difficult to distinguish these two species. The cormorant is larger and darker, it does not have a crest on the head, and it submerges its body in the water more than the Brazilian Merganser. (For more details, please see the Detailed Description).

Detailed Description

Brazilian Merganser is a slender, dark, medium-sized bird, with a typically long crest on the rear of the head. Back and wings are grayish brown. Head and neck darker with metallic dark green reflections, better seen under sunlight. The breast is pale gray with narrow darker stripes; the color of the underparts becomes paler towards the abdomen. The wing white mirror is visible during flight and it is also commonly observed when the birds are resting or swimming. The head crest is longer in the males than females. The bill is thin, narrow and serrated.

The ducklings up to one month old present the superior part of the body black, with three white spots: in the wing, side of the back and side of the tail. Juvenile Brazilian Merganser about 2 months old. Photo: Ivana LamasThe inferior part is completely white. A white band extends from the beak to the back of the eye. There is a white spot in front of the eye. The iris is gray, the beak is black, legs and feet are light grayish (Hughes et al. 2006, Partridge 1956).


No information.

Bare Parts

The bill is black. Feet and tarsi are red.


The weight is ca 700 g (females) up to 800 g (males) (Lins et al., in press). The total length varies between 55 and 68 cm.

Recommended Citation

Lamas, I. R. and L. V. Lins (2009). Brazilian Merganser (Mergus octosetaceus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.bramer1.01