ENDOCRINOLOGIC STUDIES FOR ARTIFICIAL BREEDING OF THE JAPANESE IBIS, NIPPONIA NIPPON, AN ENDANGERED AVIAN SPECIES IN ASIA

Once the Japanese ibis, or the Japanese crested ibis, was widely distributed in Asia including Japan, Korea, China and Siberia, and was not a rare species. However, this species started to disappear over its entire range beginning in the late 19th or early 20th century. Currently, only a single population of 15-20 individuals survives in wild in Yang Xian, Shaanxi, China. Several individuals, mostly immature birds, are kept in captivity in Beijing zoo. One of them is an adult male captured in 1981 in Japan and sent to Beijing zoo for breeding two years ago. In Japan, only a single old female survives in captivity. Scientists of the Japanese Ibis Preservation Center in Sado Island and Ueno zoo, Tokyo, had attempted several times to breed Japanese ibises in captivity, but they have failed in all of their attempts. In Beijing zoo, a similar attempt is now being carried out. As the basis of an artificial breeding programme of this and other species of birds, the authors have attempted to establish a noninvasive method for estimation of gonadal activities of birds and also a method to induce a complete series of the ovarian activity, i.e., ovarian growth, ovulation and oviposition, by means of hormone administration to some species of birds. In this communication, the author briefly reports recent results of these attempts in addition to results of measurements of gonadotropin levels in plasma of captive Japanese ibises and white ibises, a closely related species, Threskiornis aethiopicus.