Nature in Short / Using fieldscopes to help spot hard-to-find birds

By Kevin Short / Special to The Japan News

By Kevin Short / Special to The Japan News Happy Valentine’s Day to all our readers. The first moon of the year is already a waning gibbous, so those planning to eat their chocolate on a romantic moonlit stroll will have to wait until well after dinner. If the skies are clear in the Tokyo area beautiful Luna should be rising in the east around 9 o’clock tonight. You can also catch her sinking slowly into the western horizon early tomorrow morning.

In the park next to my condominium the witch hazel flowers are in full bloom, and I can watch rafts of waterfowl bobbing on the lake from my 20th floor veranda. I’m not what you would call a truly devoted birdwatcher, but I do like to see as many species as possible over the course of the year. Waterfowl are especially abundant and diverse during the winter months. Many common species can be observed on urban and suburban lakes and ponds, but to encounter some of the rarer types you have to wander all over the countryside.

The best way to do this is on a bicycle. Walking is just too slow to cover a range of spots. Cars are fast and convenient, but can be driven and parked only in limited areas. A bicycle allows easy access to narrow farm roads, and also to the paths along the dikes surrounding the larger rivers and marshes, which are the premier spots for finding the rarer waterfowl species.

On urban ponds the waterfowl are accustomed to people, and can usually be viewed close up. On larger, more natural bodies of water, however, the birds are often too far away to see clearly with the naked eye, or even through a pair of 8- or 10-power binoculars. To see details at these distances you need a powerful fieldscope.

Fieldscopes, also called spotting scopes, are sort of like miniature portable telescopes. They are used mounted on tripods, and deliver magnification power from 20 up to 80 times. During the winter and early spring I always pack both a fieldscope and a tripod into my rear pannier bags for countryside birding forays.

Various types of fieldscopes are available. Generally, they are classified by the diameter of their front lens. There are three basic classes, 50 millimeter, 60 millimeter and 80 millimeter. The larger the front lens the greater the ability to collect light, and the brighter the image you will see — and as might be expected, the higher the cost. A decent 50 millimeter model with a 30-40 power eyepiece costs about ¥50,000-¥60,000. The 60 millimeter models will set you back between ¥100,000-¥150,000; and the top of the line 80 or 85 millimeter scopes can easily go for over twice that!

As a destitute university professor, I make do with a Nikon ED50A. These days I frequently ride all day long, hauling the fieldscope and heavy tripod around rivers and marshes, searching for flocks of Baikal teal, called tomoegamo in Japanese, and falcated duck or yoshigamo. These are beautiful surface feeding ducks that breed on lakes and marshes in the tundra and boreal forests of eastern Russia, but spend the cold months in warmer southern climates. Here in Japan they are among the harder-to-find winter waterfowl.

Like many types of ducks the females of these two species are drab brown, but the males are decked out in truly resplendent plumage. The adult male Baikal teal is totally unmistakable. The head shows a combination of black, white, yellow and green markings. The male falcated duck has an iridescent swath of feathers extending from the eye back into a small tuft that often sticks out from behind the neck. These feathers change color from green to purple depending on the angle of the light striking them.

Ornithologists believe that the males’ bright colors serve to advertise their reproductive fitness. In fact, after the mating season is over the male ducks molt into a drab brown plumage similar to that of the females.

As winter progresses, however, these drab feathers drop off and are replaced by the colorful mating plumage. The ducks pair up on the wintering grounds, then in spring fly together to the nesting areas. At this time of year a typical flock will usually consist of both males and females.

Both the Baikal teal and the falcated duck are dabblers. They forage for algae and plankton on the water surface, and sometimes upend their bodies and thrust their necks and heads into the water to reach aquatic plants. Rarely if ever do they actually dive underwater. At night these ducks move into fallow rice fields, where they forage on the ground for fallen grains.

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


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