8. Blackbirds, USA

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When thousands of red-winged blackbirds and European starlings dropped from the sky in an Arkansas town during January of 2011, experts were baffled. Just two days later, some 500 of the same species of birds fell from the sky in Louisiana. Sickness and disease was ruled out as the cause, but the birds did appear to have suffered from internal injuries, fueling speculation that the birds may have somehow collided with each other in flight or were confused by a thunderstorm and soaked by heavy rain, driving them to into the ground.