Nature in Short / Meet the ducks that feed like whales

By Kevin Short / Special to The Japan News

By Kevin Short / Special to the Japan NewsThe new Earth-Dog year is well underway. In the traditional Asian lunar reckoning, the first moon of the year is already a waning crescent. At this phase Luna puts in her first appearance late at night, but is also visible dropping slowly through the western sky throughout the morning hours.

As the land warms and the sun returns, ducks on lakes and ponds everywhere are getting ready to make their big spring move. Ducks pair up on the wintering grounds, and at this time of year engaged couples can often be seen swimming and feeding together. The drakes, as the males are called, are decked out in their finest colorful breeding plumage, while the females are just mottled brown. The bright colors of the drakes are believed to help them attract mates and bully away rivals, and the drab plumage of the females affords some camouflage when sitting on the nest.

A typical colorful duck is the shoveler, called hashibiro gamo or“wide-billed duck” in Japanese. The drakes are unmistakable in their deep green heads, snow white chests and chestnut brown sides and belly. Another distinctive feature is a long bill that flattens and widens out at the tip, also characteristic of my favorite childhood hero and role model, Warner Brothers’ wacky cartoon character Daffy Duck.

In Toonland, Daffy’s huge wide bill caused him to lisp. For real shovelers, however, this bill is their great secret for survival. These ducks are filter feeders. The edges of the top and bottom bills are lined with fine comb-like projections that act like a sieve, allowing the ducks to efficiently strain out small invertebrates, pieces of algae and any organic matter floating on or near the surface of the water.

A pair of shovelers can often be seen swimming together in tight circles, with their wide bills held partially underwater. This method of feeding resembles that of baleen whales.

Another easily recognized winter duck is the green-winged teal, called kogamo, or “small duck” in Japanese. Even at a distance these waterfowl can be readily picked out by their small size, especially when mixed in with large mallards and pintails.

The drake has a brown head with an iridescent green patch, usually fringed in white. These small ducks frequent ponds during the daytime, but at nighttime they roam around looking for fallen grain or other food sources.

The teals’ nighttime forages often bring them into rice paddies located in narrow valleys, where local farmers still catch them with nets. One popular technique is to fill a small paddy with water and provide a supply of rice every night. Once the ducks become accustomed to the food they relax and can be readily netted.

When watching swimming ducks, keep a sharp eye out for flashes of bright color just underneath the wings. This is the speculum, or yokukyo in Japanese, a swath of startling iridescent plumage on the ducks’ secondary wing feathers. Duck speculums come in various day-glow shades of blue, green and purple. Fashionable colors such as teal-green and teal blue refer to these spectacular wing feathers.

The speculum feathers are often hidden when the duck is resting on the water, but are always clearly visible in flight. Experts seem unsure of their function. They may help the birds stay in visual contact when flying in formation.

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Short is a naturalist and cultural anthropology professor at Tokyo University Information Sciences.Speech

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