Abstract
The current ecological status of White-tailed sea eagle breeding in Hokkaido was reported and about conservation and releasing program of this species were commented. The productivity of the eagle was high in recent five years and the survival rate of young birds one and more year old was over 70 %. These results indicate that the new individual supply would be enough for increasing of this population. Therefore, it can be said that the releasing of captive breeding birds to the wild population is not necessary at present. Meanwhile, the preferable habitat for nesting has been loosed, even though around the present nest sites, timber cutting and development tend to acquiesced. It was also found that most of breeding pairs and young birds used fish discarded by the commercial fishing and the fishery factories in greater or lesser degree. It was considered that the good breeding status and the survival rate of young birds would be sustained by those discards. However, foods supplied from human activities tended to vary in the amount and might be suspended anytime. For this reason, it is hard to say that the current good status of this population would be sustained in the future. To maintain the healthy population of this species, well protection by low of the present nest sites and conservation or restoration of forests for nesting, which retain big tress, in surrounds of waterbodies, are most important tasks should be executed, instantly.
