CHARLOTTE, NC — The sidewalk outside the NASCAR Hall of Fame in uptown Charlotte was a macabre scene Tuesday evening, as more than 300 chimney swifts flew into the plate glass windows, falling to the ground badly injured, stunned or dead.

A woman who works near the Hall of Fame took a video of the scene as birds continued to hit the building. In the video, a security guard is heard saying the birds had been hitting the building for more than an hour.

A local bird rescue organization said the incident was uncommon, and something disrupted the colony of chimney swifts overnight, causing them to fly into the building, WSOC reported.

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“Grand total for tonight 310 birds,” Carolina Waterfowl Rescue said. “Roughly a third were (dead on arrival), 10 had to be euthanized, 100 are severely injured with broken wings, legs or other fractures, the other third appears stunned and will hopefully be released in a few days,” the group said.

“Chimney swifts are aerial insectivores and require hand feeding lots of worms,” the bird rescue said on its Facebook page. “It’s an expensive endeavor but these birds are an incredible contributor to our eco system and eat hundreds of mosquitos a day.”

The group said it was in immediate need of volunteers to help feed the surviving birds, which would all need to be hand fed.

Watch: Video From Outside The NASCAR Hall of Fame