A helicopter carrying 19 rock ptarmigans left a zoo bound for the Central Alps on Wednesday in the first attempt to return the extinction-threatened alpine bird to the wild in Japan.
The Nasu Animal Kingdom in Tochigi Prefecture, eastern Japan, where the ptarmigans have been bred and raised, said the birds were headed for the 2,956-meter Mt. Komagatake in Nagano Prefecture, the highest peak in the Central Alps and part of the mountain range known as the Japanese Alps.
According to Shinshu University, the wild ptarmigan population in Japan was estimated to be about 3,000 in the 1980s, but declined to less than 2,000 in the 2000s.
Last August, a female rock ptarmigan and her chicks were captured on Mt. Komagatake, and have since been bred and raised at the Tochigi zoo and Nagano Chausuyama Zoo in the city of Nagano. In the wild, hatched chicks can be killed by predators or difficult weather conditions.
Along with the 19 birds from the Tochigi zoo, three ptarmigans from the Nagano zoo will be transported to the mountain, Environment Ministry officials said.
The birds will be released after being acclimatized to their environment in a cage for about a week, the officials said, adding this will be Japan's first case in which individual rock ptarmigans that have been raised by humans are returned to the wild.
By releasing the birds, the officials hope the population of individual wild birds will increase to eventually revive large flocks of wild ptarmigans.
The birds are known for changing colors in line with the seasons.
Their summer plumage is mottled with white, black, and brown and their winter plumage is white except for the tail. A mature rock ptarmigan is about 40 centimeters in length.
The rock ptarmigan is designated a special natural monument of Japan.
