I'm not sure how many birds are dieing and seems to be mainly birds in the main than fish. IF it just a few hundred here and there it is worrying, but relax it not effecting humans so far, so need to panic just put away that shovel no need of underground bunker just yet. I'm reading that this is mainly an America issue a few reports outside of the united states, but not much. The states been effected is a vital clue to figuring out what is happening here, if mainly just southern states, you'd have to consider the possibility the BP disaster of a few months back could be the cause. That Company was spraying hell lot of dangerous chemicals to break up the oil, some of that obviously went straight up into the air, but it kind of weird, considering the time that happened and now, it would only effect the birds now a couple of months later. I'm not sure if there food has not been effected or something by this spill in the gulf. The likely explanation is sickness, it is effecting this birds and it is a strong enough sickness that the birds can't shake off by themselves! If birds start dropping out of the sky in my country, then it becomes pretty weird.