Hundreds, perhaps, even thousands of migratory birds are dying in the eastern US and Canada due to salmonella bacteria, the US National Wildlife Health Center (nwhc) announced recently. The organisation has found the bacteria in dead birds form over American 10 states since January this year and is in the process of testing corpses received from four more states. Bacteriologists are not yet sure of the strains responsible for this avian carnage and the nwhc is still to determine the exact number of birds killed so far. "We don't normally see mortality over such a broad area,' says a nwhc disease specialist. Though the exact cause of the salmonella infection has not been identified so far, scientists deduce that the bacteria that these birds carry frequently must have multiplied owing to stress. And this, they say has led to diarrhoea and severe dehydration. However, scientists also suspect that a rogue strain of the bacteria might be involved. Affected birds often fluff up their feathers to keep warm and sit still. They are usually found dead the next day.