Dozens of migratory birds were killed Tuesday night when more than 300 of them struck a building in downtown Charlotte, North Carolina, the Carolina Waterfowl Rescue group said on its verified Facebook page.

The birds, identified as chimney swifts, hit the windows of the NASCAR Hall of Fame building, according to video from CNN affiliate WSOC.

The organization said that of the 310 chimney swifts that flew into the building, roughly a third were killed and 100 were severely injured, sustaining broken wings, legs or other fractures.

Other birds appeared to be stunned and will hopefully be released in a few days, the group said.

On Wednesday morning, the organization posted a plea for volunteers to help in their recovery.

“We desperately need help feeding them and will be posting for volunteers tomorrow. They all have to be hand fed. I’m not sure how we will manage but where there is a will there is a way,” the group said.

When injured, the birds have to be hand fed lots of worms. “It’s an expensive endeavor but these birds are an incredible contributor to our ecosystem and eat hundreds of mosquitoes a day,” Carolina Waterfowl Rescue said.

The chimney swift, sometimes called a “cigar with wings” because of its appearance, is a migratory bird that travels from the United States to South America in large flocks in the fall. The birds feed on flying insects and commonly live in residential chimneys or hollow trees.

Every year, around 600 million birds die after striking tall buildings, and Chicago, Houston and Dallas are especially deadly, according to research from the Cornell Lab of Ornithology.

The problem is exacerbated by the migration’s timing, as many birds fly at night. Attracted by the glow of skyscrapers in the dark, they are vulnerable to collision — either with each other or the buildings. For some, the light can prove so disorientating that they flutter around for hours, eventually becoming exhausted and landing in inhospitable environments.

In a Facebook live video, Carolina Waterfowl Rescue said the birds most likely had been disturbed from their roosting area or were migrating.