Hundreds of birds crashed into the side of the NASCAR Hall of Fame building in North Carolina, leaving the majority of the animals dead or severely injured.
A video posted to Facebook showed a flock of birds scattered across the ground after apparently making impact with the building in uptown Charlotte on Tuesday evening. Carolina Waterfowl Rescue identified the birds as Chimney Swifts, a species that nests on vertical surfaces in dim and enclosed areas.
Of the estimated 310 birds that crashed against the building Tuesday, about a third were dead on arrival and another 10 were euthanized, according to the Carolina Waterfowl Rescue's Facebook page. Another hundred birds required further medical treatment for broken wings, legs or other fractures.
It appeared that the remaining birds were merely stunned, the rescue group reported.
The group emphasized that losing hundreds of these birds is horrible as the populations are already in decline as they lose nesting sites.
"Chimney swifts are aerial insectivores and require hand feeding lots of worms," the Carolina Waterfowl Rescue wrote. "It's an expensive endeavor but these birds are an incredible contributor to our eco system and eat hundreds of mosquitos a day."
The NASCAR Hall of Fame thanked the rescue along with other city organizations for their response in a statement obtained by NBC affiliate WCNC.
"We are saddened by this very unusual and unfortunate event, and are very appreciative of the professionalism and response of our City partners who assisted last night," the statement said. "Animal Control has confirmed there are not any health issues that might affect the public, our guests or employees."
To answer the many questions on their Facebook page about why the birds crashed into the NASCAR Hall of Fame, Carolina Waterfowl posted a link from Cornell University explaining that birds flying at night can be attracted to light shining through windows.