Wildlife officials say an unusual, sudden surge of severe weather killed at least 150 birds in central Pennsylvania last month.
State Game Commission officer Greg Graham says a deadly downward rush of air called a microburst dislodged birds roosting in trees in Leola. He says the creatures died after being slammed into trees, the ground and each other.
The reason for the massive bird kill had been a mystery for several weeks after the remains were discovered following a violent storm July 27.
The Game Commission collected 150 carcasses and sent several to a lab in Georgia. They included wrens, sparrows, robins and grackles.
Lancaster Online reports two Amish newspapers published accounts of similar bird kills that night in nearby Gordonsville and Bird-in-Hand.