Two thousand migrating snow geese have died in the northwestern US state of Idaho likely due to avian cholera, according to the state's fish and game department.

The white birds with distinctive black wingtips were headed north to their nesting grounds in northern Alaska when they died at wildlife areas in Idaho.

Carcasses of the dead geese were collected and will be incinerated to prevent the spread of disease to other predatory birds or scavengers, officials said. They do not know where the geese were infected.

Officials said the most likely cause of the deaths is avian cholera, which can cause convulsions, but wildlife experts are waiting for a laboratory confirmation.

The infection can progress so rapidly that some birds can die while flying, experts say. Studies show birds that contract the disease frequently die in six to 48 hours.

Avian cholera does not pose high risk to humans, US authorities say.

Wildlife experts observed about 20 eagles near the snow geese carcasses but are unsure if the eagles contracted the disease or can be found later if they die from it.

The disease has sporadically broken out in the Idaho region in recent decades, a wildlife fish and game official noted.