Sea Ducks (Merginae)
The seaducks, Merginae, form a subfamily of the duck, goose and swan family of birds, Anatidae.
As the name implies, most but not all, are essentially marine outside the breeding season. Many species have developed specialized salt glands to allow them to tolerate salt water, but these have not yet developed in young birds. Some of the mergansers prefer riverine habitats.
The fish-eating members of this group, such as the mergansers and Smew, have serrated edges to their bills to help them grip their prey. These are therefore often known as "sawbills". Other seaducks take molluscs or crustaceans from the sea floor.
Goldeneye are small tree-hole nesting northern hemisphere seaducks belonging to the genus Bucephala. Their plumage is black and white, and they eat fish, crustaceans and other marine life.
Their breeding habitat is the taiga. They are found in the lakes and rivers of boreal forests across Canada and the northern United States, Scandinavia and northern Russia. They are migratory and most winter in protected coastal waters or open inland waters at more temperate latitudes.
These diving birds forage underwater. Year-round, about 32% of their prey is crustaceans, 28% is aquatic insects and 10% is molluscs. Insects are the predominant prey while nesting and crustaceans are the predominant prey during migration and winter. Locally, fish eggs and aquatic plants can be important foods.
More information can be found on Wikipedia.
Although they are seaducks, most of the mergansers prefer riverine habitats, with only the Red-breasted Merganser being common at sea. These large fish-eaters typically have black-and-white, brown and/or green hues in their plumage, and most have shomewhat shaggy crests. All have serrated edges to their long and thin bills that help them grip their prey. Along with the Smew and Hooded Merganser, they are therefore often known as "sawbills".
The adult Red-breasted Merganser is 51–62 cm (20–24 in) long with a 70–86 cm (28–34 in) wingspan. It has a spiky crest and long thin red bill with serrated edges. The male has a dark head with a green sheen, a white neck with a rusty breast, a black back, and white underparts. Adult females have a rusty head and a greyish body. The juvenile is like the female, but lacks the white collar and has a smaller white wing patch.
Red-breasted Mergansers dive and swim underwater. They mainly eat small fish, but also aquatic insects, crustaceans, and frogs.
More information can be found on Wikipedia.
The Hooded Merganser is the sole surviving species in this genus.
The Hooded Merganser (Lophodytes cucullatus) is a small duck and is the only member of the genus Lophodytes. Hooded Mergansers have a crest at the back of the head which can be expanded or contracted. In adult males, this crest has a large white patch, the head is black and the sides of the duck are reddish-brown. The adult female has a reddish crest, with much of the rest of the head and body a greyish-brown. The Hooded Merganser has a sawbill but is not classified as a typical merganser.
Hooded Mergansers are short-distance migrants, and winter in the United States wherever winter temperatures allow for ice-free conditions on ponds, lakes and rivers.
More information can be found on Wikipedia.