野生トキのひな 人との共生と日中協力が大切

The Yomiuri Shimbun
Cooperation from residents, China key to returning crested ibises to wild
野生トキのひな 人との共生と日中協力が大切

A chick has been born to a pair of wild toki Japanese crested ibises — a species designated as a special natural monument — on Sado Island, Niigata Prefecture. It is the first such delightful news in 40 years. We hope the chick will grow safely.

On Sado Island, artificially raised crested ibises have been released into the wild since 2008. The number of crested ibises that have bred in nature has also increased. The chick hatched this time was born to parents who were born and grew up in nature. It is in the grandchild generation of crested ibises released into the wild.

The birth is a major milestone in the return of crested ibises to the wild.

It has been confirmed that there are currently five pairs of wild crested ibises. We probably can expect more crested ibis chicks to be born in the future as well.

The scientific name for the Japanese crested ibis is Nipponia nippon. One of its characteristics is its rose-pink — called toki color — feathers. The species used to live in a wide area of East Asia and was a familiar wild bird in Japan, too.

However, the number of crested ibises sharply dropped due to overhunting for their feathers in the Meiji era (1868-1912) and afterward as well as the deterioration of their habitat. Japanese-born crested ibises that remained on Sado Island went extinct when the last bird died in 2003.

Since 1999, the Environment Ministry has been artificially breeding the species with crested ibises donated or loaned from China. The ministry also trained them on how to catch prey. About ¥150 million is spent annually for a project to return crested ibises to the wild.

Extinct species’ revival hard

This tells how difficult it is to revive a species that once disappeared.

Cooperation from local residents is essential for returning crested ibises to the wild. The amount of agricultural chemicals used in rice paddies was reduced so that loaches and earthworms — crested ibises’ prey — can grow there, and the paddies are filled with water even in winter.

Thanks to the efforts to have crested ibises coexist with humans, about 150 crested ibises now inhabit the island.

The ministry plans to release more than 30 crested ibises into the wild every year, with the aim of having 220 birds settled in nature in 2020.

There are many challenges in breeding crested ibises in nature. The first “completely wild” crested ibis chick whose birth was confirmed this time was believed to have died soon after birth. The cause of the death is unknown, but the birds have natural enemies such as crows.

The ideal structure is for crested ibises born in the wild to increase their numbers on their own in the future by overcoming these difficulties.

To this end, it is also important to secure genetic diversity among crested ibises.

Crested ibises currently living in Japan have five crested ibises from China as ancestors, and there are many pairs that are cousins. Their ability to resist diseases and their reproductive power could diminish if those in the same consanguineous group repeatedly mate with each other. It is important to have crested ibises continually provided by China.

China is also making efforts to return crested ibises to the wild. We hope for continued mutual cooperation through crested ibises such as providing China with techniques that Japan has developed to raise the birds.

(From The Yomiuri Shimbun, May 4, 2016)


srachai について

early retired civil engineer migrated from Tokyo to Thailand
カテゴリー: 英字新聞 パーマリンク



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