Wednesday, January 12, 2011

THE ELEGANT DUCK

When we think of ducks, we may think of familiar white waddling barnyard Pekins, but in fact these waterfowl are among the most strikingly colored birds. Some of them are downright gorgeous. Look at a Wood Duck if you like brilliant iridescence. How about a Long-tailed Duck for a pleasing pattern of black, brown, and white? Or if swatches of pure color attract you, peruse a Cinnamon Teal. Of course it is the males you will be looking at, as females are generally brown; not that they aren’t beautiful in their own ways.

The Northern Pintail (Anas acuta), not the most brightly colored of ducks, is surely the most elegant. The long, swanlike neck of the male of this species contributes to the look of elegance, as do the long, sweeping central tail feathers. The subdued gray and white body and rich dark brown head add patrician colors to the attractive shape. Even the females, somewhat smaller than the males, have longer necks than those of other ducks.


Why the long neck? Well, dabbling ducks often feed by upending in shallow water, their tail up in the air and their head and neck submerged to sample underwater fare such as leaves, buds, and seeds of aquatic plants and a great variety of invertebrates. You can only reach so far with an average-length neck, and over time pintails just outreached the competition by evolving that long neck. By feeding in water too deep for their near relatives, they presumably were able to take advantage of resources unavailable to the others.

But it must be added that most of the feeding done by pintails is in very shallow water or on land, where they take seeds from sedges and grasses. On their wintering grounds, they are very common among the dabbling ducks that feed on marine invertebrates on mudflats as the tide goes out. The long neck also serves them well in those situations, allowing a foraging bird to reach all around it. This adaptable species is one of the most abundant ducks in western wetlands.

As in other temperate-zone ducks, pair bonds are formed in fall and early winter, and you can expect to see pintail pairs from then on until the female has laid her 5-10 eggs. Male courtship consists of ritualized displays and vocalizations, with head up, bill down, and tail up prominent components. That long, slinky tail is surely impressive at this point. Females are impressed by both the intensity of courtship displays and the constant attentiveness of the courting male. Some of the choice may also involve appearance, males with more colorful scapulars and whiter breasts preferred.


Because mortality is heavier on females than males in most ducks, there is a surplus of males in late winter and spring after all the females are paired up. In this and other dabbling ducks, it is common to see groups of males in pursuit of a single female. These pursuit flights can involve up to a dozen males – although usually just a few – and last for many minutes. They may end with a forced copulation when the female is forced down on land, or the female may “escape” only to be harassed by other males that spot her. The female may have to be mated to avoid this.

Prime pintail breeding habitat is a shallow marsh. Because such marshes are subject to disappearance during any extended drought, they come and go in the landscape, and so do pintails. During wet years, they do well, and their numbers increase. During widespread droughts, the opposite is the case. Breeding populations wax and wane and have varied from about 2 million to about 10 million birds in recent decades.

Dennis Paulson

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