Mottled Duck — Length: 22 inches Wing span: 30 inches
A large dabbling duck closely related to the Mallard and the American Black Duck, the Mottled Duck occupies southernmost portions of the eastern U.S. Mottled Ducks are sometimes seen in 3-bird flights in which a territorial male is chasing away an intruding pair. Mottled ducks are less commonly seen in flocks than most other ducks.
Mottled Ducks are thought to begin breeding at one year of age. Predation and hunting are major sources of mortality, although hurricanes can also have effects on populations. The record known age for a Mottled Duck in the wild is 13 years.
Ok, what is above duck? It has a very dark crown and strong line through the eye. The bill is fairly heavy and dark, olive green. There is a sharp contrast between the pale neck and the dark body. At least in the photo the feather edgings are narrower and less buffy orange than on the Mottled Ducks pictured above and below.
The Sibley Guide to Birds says:
Mottled Duck is “distinguished from American Black Duck by overall warmer color with pale markings on most body feathers: clean buffy throat: paler crown and supercillium; black spot on gape.”
The Sibley guide also says the Mottled is always buffier than the American Black Duck.
The very dark crown and dark body that is clearly not as buffy as the Mottled Ducks pictured points to this duck being an American Black Duck. The black spot at the base of the bill indicates Mottled duck. The bird was photographed in Rockport, Texas, where American Black Ducks are extremely rare.
There is a dark race of the Mottled Duck in the western Gulf Coast, and this might be a representative of that race.
Or maybe this is a juvenile Mottled Duck, which can be darker than the adult and have an olive bill.
All of the above is said just to point out how confusing the female Mallard, Mottled Duck and American Black Duck can be. Using a combination of field marks, location and time of year can be the best way to come to an accurate identification.
Mallards rarely hybridize with Mottled Ducks but some authorities consider them the same species.
The body is darker than female Mallard and lighter than American Black Duck. Throat and face unstreaked. No white in the tail.
The bird on the left is interesting. It is hanging out with a male Mottled Duck. It has a black spot at the base of the bill, not found on Mallards. However, the bill is orange with black markings, typical of a female Mallard. Most field guides indicate females have an olive green or yellow green bill without markings. When you scroll down the page you will see three additional images that show females with orange bills. Perhaps these are all hybrid females but I have seen numerous female Mottled Ducks on the Texas coast with orange bills, some with dark markings as with the above bird.