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EAFES Symposium ES08-3

How do reintroduced crested ibises rely on paddies and Satoyama landscape?

NAGATA, H (Niigata Univ)

The crested ibis (Nipponia nippon) used to be widespread in Japan, but the species was extinct in the wild. In order to reestablish a wild population, re-introduction programme has been implemented on Sado Island since 2005. To date 78 ibis have been released since 2008. Paddy fields were the main foraging habitat in spring, early summer, autumn and winter. But, they cannot use rice paddies as a foraging site because of full-growth of rice. In late summer, they often used mounds around paddies, grasslands, and set-aside paddies. Ibisses were mainly dependent on loaches, earthworms, amphibians, and insects throughout the year. Loach was predominated food items except for summer and occupied nearly 20% of swallows, but it was estimated to occupy from 40% to 50% weight of food items swallowed. Ibises depend on terrestrial invertebrates, including earthworms, particularly in late summer. Small invertebrates were important prey items of ibises in terms of frequency (70–90%) throughout the year. Preliminary GIS analysis showed ibises preferred paddies surrounding by forest and small hills, which was situated at lower area with steady slope. This kind of landscape is called ‘Yato’ in Japanese, which is developped between hills and plains at alluvian fans in Saoyama landscape. ‘Yato’ landscape might provide the ibis both foraging and resting habitats.


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