Widely distributed throughout the Northern Hemisphere, the Eurasian Teal migrates to Japan as a winter bird, settling on rivers or marshes. Smaller in size than the Spot-billed Duck and the Mallard, it prefers a watery habitat with thick reeds and a relatively narrow water surface. Females (above photo) and males just arrived in Japan have dull coloring, while males change to beautiful winter plumage in anticipation of courtship and call out with a voice that sounds like a flute.
Play birds singing
Teals of North America are presumed to breed in Alaska, Teals of Europe in Scandinavia, and Teals of Japan in Far East Russia. They begin to appear in Japan in autumn and can be seen until around the beginning of May, but since they are widely distributed throughout northern Asia and Far East Russia, there are also some that are passage migrants to Japan. It is also possible that Teals that come to Japan in September are heading for Southeast Asia for the winter, and those that are around until May could be ones that have wintered south of Japan and made a stopover in Japan as they head north to their breeding ground.
Even in September, when males have not yet changed their plumage and so still look like females, you should be able to identify the Common Teal since, on top of having the characteristic wide, flat bill of a duck, it is much smaller than the Spot-billed Duck. Males become more beautiful as autumn progresses into winter, and at the beginning of the year they start their courtship rituals. Females choose the male they wish to mate with, and the male becomes her bodyguard.
I have a difficult time answering when in autumn or winter people ask, “Where can I see young Common Teals in Japan?” Scenes of parents with their young ducklings, such as with Spot-billed Ducks, can only be observed at their breeding ground in Japan or elsewhere in early summer.
However, Common Teals that come across the sea to Japan make the trip when the ducklings that have been born in Russia in the spring are grown to the same size as their parents and are now independent, so the parent-child relationship no longer exists. Past autumn it is not easy to tell the age of a bird since they grow quickly, and, as explained in the profile of the Mandarin Duck, the relationship between the parents is only for the duration of the mating season, so we can say that the low survival rate in the natural world is no surprise.
Although not as common as the Common Teal, there are other small pigeon-sized ducks, including the Garganey and the Baikal Teal. The pattern on their spread wings is the key to distinguishing the species when looking at females or males that have not changed to winter plumage. As shown in the top photo, the time when drying their wings after bathing provides a good opportunity to see the characteristic feather pattern of the Common Teal, a patch of iridescent color on the secondary feathers, called the speculum, bordered by a wider white belt above and narrower below. And the two white belts on the Gargany are about same width. On the other hand, the Baikal Teal has one single white belt to the rear.
Male ducks display the distinctive plumage of their species from autumn onward (females of all species look similar throughout the year). A rare visitor to Japan, the male Green-winged Teal also becomes easy to identify when it changes to its winter (breeding) plumage. In contrast to the male Eurasian Teal with its horizontal belts of white, the male American Green-winged Teal has a vertical white stripe on each side of its chest, so that is how you can distinguish them from each other.
The male in the center is in the middle of his courtship dance; the iridescent green on his wings and face as well as the triangular yellowish mark on his rump stand out as he strikes a pose to attract a female.
Canon sites where this bird is seen