Mergansers have a crest that, like a fan, can be spread or closed.
Like other mergansers, it has a narrow, serrate bill. The male
in breeding plumage is distinctive, with olive-brown sides and
a black back accented with white stripes down the middle of a
few long feathers. His breast is white with two black bars on
each side. The black border surrounding the white crest extends
to the face, which is punctuated with a yellow eye. Females are
brown-gray overall, lighter below and darker on the back. The
crest of the female is reddish-brown. The juvenile looks like
the female, as does the male in non-breeding plumage, although
his crest is browner.
forested, freshwater wetlands with emergent vegetation are the
preferred breeding habitat of the Hooded Merganser. They have
been known to breed in more open habitat when nest boxes are
available. Low-elevation freshwater lakes, ponds, sloughs, and
slow-moving rivers are all used. During migration, they visit
a wider range of habitats, and are often found on open water,
along river banks, and in coastal bays and tidal creeks. In winter,
they are found in woodland ponds and swamps, as well as coastal
estuaries, bays, and inlets. While they are found in brackish
and salt water, they generally prefer fresh water.
dramatic courtship displays of the Hooded Merganser are apparent
on the wintering grounds where groups gather in small flocks
and most pair formation begins. During these displays, the male
fans his crest.
Mergansers have a more diverse diet than that of other mergansers.
Small fish, crustaceans--especially crayfish, and aquatic insects
are all common prey items. Insects are especially important for
the young. Hooded Mergansers have underwater vision, which helps
them forage while diving.
females often prospect for potential nest sites for the following
year, and generally start breeding at the age of two. Pair bonds
last from winter until incubation begins. It is uncertain whether
bonds reform the following year, or if all pairing begins anew.
Hooded Mergansers nest in cavities 10 to 50 feet up a tree or
in nest boxes. The nest is made from materials found in the cavity
and lined with down. The female lays 10 to 12 eggs, and commonly
lays eggs in the nests of other Hooded Mergansers and those of
other cavity-nesting ducks. Incubation is by the female alone
and lasts for 26 to 41 days, averaging 33 days. When incubation
starts, the male leaves the nesting area. Within 24 hours of
hatching, the young jump to the ground and head to the water.
Here they can swim well and find their own food. The female tends
them and leads them to food-rich areas for a few weeks, but abandons
them before they can fly, at around 70 days.
Mergansers migrate short distances. They have usually left coastal
wintering areas by April and return in mid-November.
destruction and the loss of nesting cavities have undoubtedly
resulted in a decline, although in recent decades numbers have
stabilized and appear to be on the increase in many areas with
the help of nest boxes and wetland-restoration efforts. Hooded
Mergansers have a relatively small population and low productivity
rates due to their delayed onset of breeding (not breeding until
age two). They are also slow to colonize new breeding areas,
making it more important to conserve the areas where this duck
is currently breeding.