Duck With An Upturned Tail

By BILL CHAISSON
Of a Feather
On Wednesday someone reported on the N.H. Bird Forum seeing 50 ruddy ducks. They were floating in an unlikely spot: the top pond of the Exeter Wastewater Treatment Plant. As it happens, on Monday,

I saw what looked like a single ruddy duck. It was sitting in a fire pond on N.H. Rt. 4A in Wilmot Center. (The fire pond is mandated to put out conflagrations in the adjacent subdivision; we don’t have hydrants in this town.) I was driving by with the dog whining in the back seat because she (really, really) wanted to go for a walk (and not on Rt. 4A). I didn’t stop.

It is the migratory season now, which is why it was strange that a ruddy duck spent a month at the Rochester Wastewater Treatment Plant and was still there on Aug. 4. It was included in the forum’s Rare Bird Alert because this bird nests on the Great Plains, southern West Coast, and with an isolated population through the Great Lakes. It was awfully early for it to be in eastern New England. It was still there on Sept. 1.

No more were reported on the forum until the October 25 sighting of 50 in Exeter. The Birds of New Hampshire describes the species as a “regular fall migrant but in highly variable numbers from year to year. Only occasional on spring migration, though some increase noted in recent years. Very infrequent summer straggler; rare in winter.” This reference notes it was once moderately common but declined sharply around the turn of the 20th century—the market hunting era—and only began to recover after the 1930s. In the 1980s there was another decline, from which it has been recovering since the 1990s.

The ruddy duck (Oxyura jamaicensis) is the original “odd duck” in a lot of ways. Taxonomically, it is rather singular. It is the only member of its genus in North America. There are two species in South America, one in Eurasia, one in Australia, and one in Africa. Collectively they are referred to as the “stiff-tailed ducks.” As their name implies, their tail feathers are long, spiky, and often held erect (straight up!) when the bird is at rest on the water’s surface.

In addition to their strange tails, ruddy ducks are rather small (15 inches long) birds and have very large, swollen-looking bills that are bright blue during the breeding season. The male has a cinnamon-colored body with black on the crown and nape and broad patches of white on the cheeks. The females are gray with fine mottling and there is a broad dark line through the smudgy white of the cheeks.

It is typically most seen in New Hampshire during the last two weeks of October and the first week of November. So, we do not often get to see it in its breeding finery. This time of year, the males look much like the gray females except their cheeks are still entirely white. The bills of the non-breeding birds are grayish.

These are diving ducks with legs so far back on their bodies they cannot walk on land at all. Rather, they push themselves around on their chests on the rare occasions when they leave the water. Captive birds are reported to learn to walk upright like penguins, but with great effort.

These ducks are remarkably silent, except during the breeding season, when they are also highly aggressive. As part of its breeding display the males are said to make a sound like belching, made with inflatable throat sacs, and when they take off (which requires a long stretch of pattering) they make popping sounds on the water with their feet. Females make high pitched sounds to call their broods and hiss at intruders during the breeding season.

As might be expected from birds with so many unique characteristics, their relatedness to other ducks is not well understood. In fact, at present they are thought to be more closely allied with swans and geese than other ducks. Other “stiff tailed” duck species include the masked duck (Nomonyx dominicus) of the Caribbean, Mexican Gulf coast, which is regarded as a sort of “missing link” between the Oxyura species and some distant ancestral extinct duck. The musk duck (Biziura lobata) of Australia also has a long stiff tail and, during its breeding season, a distinct odor and strange lobate sac that descends from its bill.

Like the ruddy duck, the musk duck is highly aquatic and very awkward on land. The masked duck, however, gets about ashore with relative ease. It also takes off directly from the water like a dabbling duck rather than needing a running start like most diving ducks.

Molecular genetic work done by Kevin McCracken (Louisiana State University) and others in 1999 showed the Oxyura species and the masked duck to be sister groups. The musk duck is unrelated, its stiff tail and rearward-placed hind limbs being convergent characters. Before this DNA work was done, the stiff-tailed ducks were thought to be more closely allied with other diving ducks based on shared morphological characters. Those are now understood to be examples of convergent evolution as well.

The New World Oxyura species, the ruddy duck and the Andean duck (O. ferruginea) are so closely related they were once considered a single species. In 1998 the American Ornithological Union separated them, but they are still known to hybridize. There may even be a hybrid population in northern South America, where their ranges overlap.

The ruddy duck was accidentally introduced to England (escapes from collections) in the 1950s, was breeding in the wild by the 1960s, and began to spread through Europe, where it bred with the endangered white-headed duck (O. leucocephala). It was considered a pest and eradication programs followed. It is now on the decline in the Old World.

— Bill Chaisson has been a birdwatcher for over 50 years. These columns arearchived at shinhollow.wordpress.com.