Kingfishers are among the most popular birds. Whenever one appears on a nature hike it is always greeted with oohs and aahs. Japan is home to several species of kingfisher, but the one seen the most in the southern Kanto region is the common kingfisher, or kawa-semi in Japanese.
The kawa-semi is a tiny bird, with a body no bigger than that of a sparrow. An incredibly colorful plumage, however, makes this little guy visible at a considerable distance. Just a quick flash of cobalt blue and rusty red skimming over the water or along the edge of the forest, and you know there’s a kingfisher come to work.
Despite their Japanese name, which means “river-kingfisher,” the kawa-semi are very much at home on small ponds. They especially like ponds or lakes with trees growing right down to the water’s edge. The branches that stick out over the water make perfect perches. Also, fish tend to congregate in the shaded waters underneath the overhangs.
Kingfishers hunt by a method that ornithologists call plunge diving. They sit on a perch, scanning the waters below for fish. When they pick out a likely victim, they plummet straight down, hitting the water with a splash.
Kingfishers, however, do not engage in underwater pursuit, actively chasing their prey through the water like cormorants or grebes. If they do not get their fish on the initial plunge, they fly back up to the perch and try again. The kawa-semi, small as they are, are equipped with a long, thick, powerful beak, capable of grabbing and holding a small fish. Kingfishers do not tear their prey up like eagles, owls or crows. They simply swallow them whole. To avoid getting the fish’s fins caught in the throat, the birds juggle it around in their mouth, maneuvering it into perfect position to swallow head first.
Another typical kingfisher behavior is slamming its prey repeatedly against a branch. This functions to kill or stun the prey, and stops it from jumping around and possibly escaping. It may also serve to crush some of the prey’s bones, making it easier to swallow.
Kawa-semi are year-round resident birds all over Japan. They are common on the irrigation ponds, small lakes and marshes throughout the countryside, and can even be seen on most inner-city park ponds. These kingfishers nest in holes dug horizontally into steep slopes. The slope has to be long and steep enough to prevent weasels from reaching the nest, either from below or above.
Rat snakes also have a taste for kingfisher eggs and chicks. These snakes are excellent climbers, and will slither into a poorly located nest hole.
Some of the best spots to enjoy watching kawa-semi are small irrigation ponds found at the head of narrow valleys. These ponds are partly manmade, and are designed to collect the water that naturally seeps out of the valley sides. They originally supplied water to downstream rice paddies. In most areas, they no longer serve this function, but many have been preserved because of the widespread folk belief that spots where water seeps out of the earth are sacred.
These ponds, called tameike in Japanese, can be found all over the rice paddy countryside. Even in the cities, many have been incorporated into public parks and gardens. Shinobazu no ike pond and the ponds in Inokashira and Shakujii parks in Tokyo are good examples. In most cases, the irrigation ponds are surrounded by trees, or at least substantial clusters of reeds and cattails, making them ideal kingfisher hunting habitat.
A typical traditional irrigation pond contains a small island on which sits the shrine housing the local suijin, or water spirit. Various deities do duty as water spirits, but the most popular by far is Benzaiten, a goddess originating in India. Benzaiten, or Sarasvati, is thought to have been an ancient river spirit that was later incorporated into the Buddhist pantheon.
Here in Japan, Benzaiten adopts multiple spiritual roles. As one of the Shichi-Fukujin or “Seven Lucky Gods,” she is a bringer of prosperity and wealth. This goddess is also the patron saint of music, language and the performing arts, and is usually depicted seated, playing a traditional Japanese stringed instrument called a biwa.
Out in the rice paddy countryside, Benzaiten serves primarily as a suijin water spirit. Her tame-ike irrigation ponds are usually protected from development, and frequently function as local biodiversity preserves, not only for kingfishers, but also for aquatic plants and insects, and amphibians such as frogs and newts.
Another Japanese kingfisher, the yama-semi (literally “mountain kingfisher”), or greater pied kingfisher as it is called in English, prefers to live along heavily forested streams higher up in the mountains. These are much bigger birds, easily twice the size of the kawa-semi. Their plumage is a mottled mixture of black and white, and they show a distinctive shaggy crest at the back of heir heads.
The yama-semi are year-round resident birds, but the spectacular ruddy kingfishers (aka-shobin), with their rufous plumage and bright red bills, are just summer visitors here in Japan. In winter they migrate southward. Two other species, the black-capped kingfisher (yama-shobin) and collared kingfisher (nanyo-shobin) are occasionally spotted in southern Japan; while the Miyako kingfisher (Miyako-shobin) is totally extinct. Only one specimen of this species has ever been found, in 1887 on Miyakojima island in southern Okinawa Prefecture.
Short is a naturalist and cultural anthropology professor at Tokyo University of Information Sciences.