LEAD POISONING OF STELLER'S AND WHITE-TAILED SEA EAGLES IN HOKKAIDO, JAPAN.
Nobumichi Kurosawa (Hokkaido Veterinary Medical Association)
Lead poisoning of eagles in Japan was first reported in February 1996 in Abashiri, north-eastern Hokkaido. A Steller's Sea Eagle was found dead with lead shots in the stomach, suggesting a secondary poisoning through waterfowl, as the cases in North American Bald Eagles. After 1997, however, more dead eagles were found in the districts of Abashiri, and Kushiro nearby. X-ray examinations discovered irregular shaped metal objects in their stomachs. Autopsies showed that these metals were pieces of lead, and that there was deer fur in the stomach contents. The result indicated that lead poisoning was related to deer carcass. Later researches revealed that lead poisoning in the eagles, starting in 1995 (confirmed in 1996) rapidly increased until 1998, with the total mortality of 24 Steller's Sea Eagles, and six White-tailed Sea Eagles. Most of the cases of lead poisoning were caused by rifle bullets used for deer hunting, except for one case in 1996. The lead poisoning incidents increased as the deer hunting increased. The areas where the poisoned birds were found coincided with the areas of high deer hunting pressure or deer control area. Hokkaido government made a survey on the causes of the eagle mortality and acknowledged the relation between the death of eagles and the deer hunting. It is estimated that lead poisoning accounts for about 80 % of the mortality of the eagles wintering in Hokkaido. The adult birds seemed to be most vulnerable to lead poisoning, which may result in the decline of the species in the near future.