The sea ducks (''Mergini'') are a tribe of the
duck subfamily of
birds, the
Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group spend their winters near coastal waters. Many species have developed specialized salt glands to allow them to tolerate salt water, but these are poorly developed in juveniles. Some of the species prefer riverine habitats. All but two of the 22 species in this group live in far northern latitudes.
The fish-eating members of this group, such as the
mergansers
''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird.
The common merganser (''Merg ...
and
smew
The smew (''Mergellus albellus'') is a species of duck, and is the only living member of the genus ''Mergellus''. ''Mergellus'' is a diminutive of '' Mergus'' and ''albellus'' is from Latin ''albus'' "white". This genus is closely related to ' ...
, have serrated edges to their bills to help them grip their prey and are often known as "sawbills". Other sea ducks forage by diving underwater, taking molluscs or crustaceans from the sea floor. The Mergini take on the
eclipse plumage during the late summer and molt into their breeding plumage during the winter.
Species
There are twenty-two species in ten
genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
:
*Genus ''
Clangula''
**
Long-tailed duck (formerly
oldsquaw) (''Clangula hyemalis'')
*Genus ''
Histrionicus''
**
Harlequin duck (''Histrionicus histrionicus'')
*Genus †''
Camptorhynchus''
** †
Labrador duck (''Camptorhynchus labradorius'') (
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
)
*Genus ''
Polysticta
Steller's eider (''Polysticta stelleri'') is a migrating Arctic diving duck that breeds along the coastlines of eastern Russia and Alaska. It is the rarest, smallest, and fastest flying of the eider species. Amongst the Inupiat, Steller's eider is ...
''
**
Steller's eider (''Polysticta stelleri'')
*Genus ''
Somateria'', the eiders. These are large marine ducks. The drakes have body plumage showing varying amounts of black and white, and distinctive head patterns. Females are brown.
**
Spectacled eider (''Somateria fischeri'')
**
Common eider (''Somateria mollissima'')
**
King eider (''Somateria spectabilis'')
*Genus ''
Melanitta
The scoters are stocky seaducks in the genus ''Melanitta''. The drakes are mostly black and have swollen bills, the females are brown. They breed in the far north of Europe, Asia, and North America, and winter farther south in temperate zones of ...
'', the scoters. These are stocky marine ducks. The drakes are mostly black and have swollen bills. Females are brown.
**
Common scoter (''Melanitta nigra'')
**
Black scoter or
American scoter (''Melanitta americana'') (sometimes considered a
subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
of ''M. nigra'')
**
Velvet scoter (''Melanitta fusca'')
**
White-winged scoter (''Melanitta deglandi'') (sometimes considered a subspecies of ''M. fusca'')
**
Surf scoter (''Melanitta perspicillata'')
*Genus ''
Bucephala'', the goldeneyes. These are less marine than some species in this group, and will winter on fresh water. Drakes have white bodies with black backs and distinctive head markings. Females are grey with chestnut heads.
**
Common goldeneye (''Bucephala clangula'')
**
Barrow's goldeneye (''Bucephala islandica'')
**
Bufflehead
The bufflehead (''Bucephala albeola'') is a small sea duck of the genus ''Bucephala'', the goldeneyes. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of ''Systema Naturae'' as ''Anas albeola''.
The genus na ...
(''Bucephala albeola'')
*Genus ''
Mergellus'' (sometimes included in ''Mergus'')
**
Smew
The smew (''Mergellus albellus'') is a species of duck, and is the only living member of the genus ''Mergellus''. ''Mergellus'' is a diminutive of '' Mergus'' and ''albellus'' is from Latin ''albus'' "white". This genus is closely related to ' ...
(''Mergellus albellus'')
*Genus ''
Lophodytes'' (sometimes included in ''Mergus'')
**
Hooded merganser (''Lophodytes cucullatus'')
*Genus ''
Mergus
''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird.
The common merganser (''Merg ...
'', the typical mergansers. These are the least marine of this group, only red-breasted and common mergansers being common on the sea. These are large saw-billed ducks which dive for fish.
**
Red-breasted merganser (''Mergus serrator'')
** †
New Zealand merganser (''Mergus australis'')
**
Common merganser or
goosander (''Mergus merganser'')
**
Brazilian merganser (''Mergus octosetaceus'')
**
Scaly-sided merganser (''Mergus squamatus'')
Below is a phylogeny based on a mitogenomic study of the placement of the Labrador duck and the diving "goose" ''
Chendytes
''Chendytes lawi'' is an extinct, goose-sized flightless marine duck, once common on the California coast, the California Channel Islands, and possibly southern Oregon. It lived in the Pleistocene and survived into the Holocene. It appears to ha ...
lawi''.
References
SeaDucks.org - Science and Management Reference
{{Taxonbar, from=Q33176341