The mid-afternoon attack at Tysslingen lake in central Sweden Sunday disrupted a peaceful scene for the birds and bird-watchers,The Local reported.
"Suddenly we heard the explosions and the swans become very upset. Then we saw rockets coming toward the swans, which went into a panic and began trampling one another. And several got stuck in a chain-link fence," said John Hall, a freelance photographer.
It was "total chaos," said another onlooker.
"Every bird disappeared and there was nothing left to see," said Helny Olsson. "It [was] so gruesome, so deplorable. It was either a stupid prank, or it could be so bad that there are some who got annoyed by the birds and their song."
The birds eventually returned to Tysslingen.
Video of Victoria’s Secret models trying to 'twerk' hits Instagram
Megyn Kelly: Santa Claus and Jesus are both white men