The Red-crowned Crane, with a wingspan of up to 240 cm, is the largest wild bird in Japan. It breeds in the wetlands of eastern Hokkaido and, in order to reach adult size, its palm-sized chicks must eat plenty of the small animals abundant in marshy areas. In fall and winter, most birds gather at man-made feeding grounds while a few will occasionally migrate from Hokkaido to areas further south on Japan's main island, Honshu. Cranes are thought to be monogamous, maintaining a lifelong relationship with the same partner. When a pair performs a duet, the male sings “coh” and the female follows with a “ka-ka”.
Play birds singing
Red-crowned Cranes, which were once thought to be extinct, were rediscovered in the Kushiro region of Hokkaido during the Taisho period (1912-1926) and it is well known worldwide that their population was increased with the help of assisted feeding during winter. Recently, the crane's breeding spots and wintering spots have been found on the Eurasian Continent. In Japan, conservation of the wetlands that the birds need to breed has become an issue. Assisted feeding has continued, but has created an undesirable situation whereby so many cranes flock together in the same place that an infectious disease could spread rapidly and cause them to suddenly become extinct. Other emerging issues are how to increase the number of independent cranes that do not need human assistance and can feed themselves in the wild during winter, and how to disperse their habitats.
The Wild Bird Society of Japan established the Tsurui-Ito Tancho Sanctuary for Red-crowned Cranes and has been conducting research, engaging in wetland conservation and creating natural feeding grounds.
Red-crowned Cranes, which breed in Russia and China, journey south for the winter. They sometimes visit the wintering spots of White-naped Cranes and Hooded Cranes in Kagoshima Prefecture, and may migrate further south from the Eurasian Continent.
Thanks to research conducted using satellites that track migratory birds, we have discovered an important stopover location for White-naped Cranes and Hooded Cranes from the continent, and a wintering spot for Red-crowned Cranes after they breed on the continent: the Korean Demilitarized Zone, which divides the Korean Peninsula into North Korea and South Korea. Dr. Higuchi Hiroyoshi, leader of the research, said, “ If we can protect the nature of the demilitarized zone, which came into being through the unfortunate history of human beings, it would become a historically significant symbol of our resolution to never cause such misery again.”
Red-crowned Cranes are often depicted with a black tail, but actually their tails are white. At rest, the bird's tail is completely covered with its long, black tertiary feathers, so at first sight, the tail looks black.
In early spring, a pair will dance to confirm their love. Occasionally, chicks born the previous year-whose heads are a dark brown-will try to imitate their dance, but the parents won't allow it. By spring, the parents will leave their chicks and proceed to the next breeding season.