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Foundation Newsletter Tamagawa

No.130"Somechi at Tamagawa river"

Reports from our Seasonal newsletters
Special Edition on the Annual Report about the Foundation’s Projects
No.130"Somechi at Tamagawa river"
The Foundation Newsletter, Tamagawa (English Version)

The Tama River at Somechi

Getting off the train at the Komae Station on the Odakyu Line, I took the bus bound for Tamagawa Jutaku Chuou to the Tamagawa Jutaku Minami-guchi bus stop. Going up the riverbank on my left, there I was facing the Tama River. Walking through a wide stretch of the riverbed down to the edge of the river, I was greeted by the slow, quiet but rich water of the river gently meandering there. Looking upstream, I was embraced by a grand view of the river with a backdrop of the peaks of the Tanzawa Mountains and lower rolling hills.

I sensed the bounty of nature, finding people fishing and some egrets occasionally flying over and feeding on the shore.

 

Photo & Text Hidehiko Endo

[Opening Article]

Black-headed Ibis of The Tama River


Teruyuki Komiya

Director, Ueno Zoological Gardens

Selection Committee Member, The Tokyu Foundation for Better Environment

 

The Japanese crested ibis (Nipponia nippon), once extinct, is now on the road to restoration in the Sado Island (Niigata Prefecture). I engaged in its ex-situ conservation from 1972 to 1986, when I was working as part of the breeding staff at Tama Zoological Park (Tama Zoo) in Tokyo. Ex-situ conservation is a process of breeding and protecting a species at the brink of extinction outside its natural habitats, while in-situ conservation means preserving a species inside its natural habitat. If a species is considered difficult to be preserved within its habitat, ex-situ conservation comes on the scene as a supplement to in-situ conservation.

 

In 1953, one crested ibis that was injured and caught by a steel trap in Sado was sent to Ueno Zoological Gardens (Ueno Zoo) in Tokyo. Starting with this incident, the zoo launched a breeding project of black-headed ibis (Threskiornis melanocephalus) in 1958, and after 11 long years, it finally succeeded in their breeding in 1969. It was through this kind of simulation experiments using relative species such as black-headed ibis, the study and preparation for the ex-situ conservation of the crested ibis were carried out.

 

Since then for over half a century, the zoo has been involved in supporting the crested ibis ex-situ conservation in the Sado Island. Various techniques, such as artificial incubation, artificial brooding, artificial diet, parasite removal, surgery, anesthesia and chick sexing, were developed.

 

By the way, do you remember seeing black-headed ibises around the Tama River from 1983 to 1999? Well, they were the ones we bred and released from the Tama Zoo when I was working there as their keeper.

 

There is a stuffed specimen of black-headed ibis, captured in Kameido in Tokyo in 1883, in the Yamashina Institute for Ornithology. In the Edo period (1603-1868), black-headed ibises were widely found in the Kanto area, and were often depicted in picture scrolls. Their inhabitation and propagation were also documented under the name of kurokubi (black neck), kamasagi (sickle heron)or nabekamuri (wearing pan on the head) in old records written during that period.

 

In the autumn of 1983, after a hundred years since the capture in Kameido, five young black-headed ibises flew in formation over the Tama River. All of them were hatched in the Tama Zoo that summer.

 

The first reason for their release was to find out whether artificially bred ibises could survive in the natural environments. Before releasing the extra rare crested ibises to nature, we wanted to carry out the experiments with black-headed ibises.

 

The second reason to release the black-headed ibis, and not the scarlet ibis (Eudocimus ruber) nor the northern bald ibis (Geronticus eremita), populations of which were increasing at that time, was our wish to have the black-headed ibis, once a very familiar wild bird living in Japan, thrive again in the wild. The black-headed ibis is not extinct as a species, but in Japan it died out earlier than the crested ibis. Since it doesn’t have the graceful colored feathers of the crested ibis, the poor bird had attracted only the slightest attention.

 

There were two concerns at that time. The first was whether the black-headed ibis was really a native species to Japan. If not, our attempt would only mean releasing a non-native species to Japan. And the second was whether it could really survive in the wild.

 

Regarding the first concern, I can just say that unless we believe and take the contents of picture scrolls or old documents as evidence of their existence, nature restoration efforts can go nowhere. For the second one, I wasn’t able to give an immediate answer. The last freed black-headed ibis died on March 19 in 1999. At that time, I was working at the Tama Zoo as chief of breeding staff, and was observing the released troop of black-headed ibis. That day, I went to check their roost in the zoo as usual and found the body. Now, I can tell you that the artificially bred black-headed ibis was able to survive in the wild for 15 years and 9 months.

 

The troop of black-headed ibises that dwelled in the Tama River basins with a flock of herons was not just birds that got out of their cages. Rather, they were pioneering birds for exploring the possibilities of resurrection of the Japanese crested ibis.

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