Bird sanctuaries, poultry farms and zoos were put on high alert last month after the migratory birds in some region were found dead, The New York Times reported Monday.
The Times cited Japanese media reports collected by ProMED, which monitors disease outbreaks. The reports included one that a hooded crane was found dead on the Izumi Plain in Kagoshima Prefecture in southern Japan, the largest wild crane wintering site and the nation's leading poultry-raising area.
The reports said 23 birds were found dead following a search in Tottori in the north. The birds were being tested.
In Toyama Prefecture, also in the north, a dead mute swan led to inspections of nearby poultry farms. In Hyogo Prefecture on Japan's Inland Sea, officials decided to stop displaying white storks, a national treasure, to prevent exposure to any likely infected wild birds.