From NYC Bird Alliance

NYC Bird Alliance was very troubled to hear about work conducted today on the Upper West Side water tower that, up until last night, was home to Manhattan's first Barn Owl nest. The construction work destroyed part of the tower, removing the roof. There is a high likelihood that this work disturbed the #BarnOwl pair and the five or six fledglings.

Active nests of migratory birds are protected under federal and state law and the building is required to pause any work on the water tower and near the nest. The destruction of a nest constitutes a wildlife crime. NYC Bird Alliance responded immediately by alerting the New York State Department of Environmental Conservation (New York State Department of Environmental Conservation) and U.S. Fish and Wildlife Service (U.S. Fish and Wildlife Service), and met with the building's super to ensure all future planned work is halted until the owls have all left this nesting site.

NPR article about why this nest is so significant, plus more owl pics.

Otherwise, tl;dr -

"It was, like, totally shocking," Andrew Farnsworth, a migration ecologist at the Cornell Lab of Ornithology, said of the barn owls. "To the best of our knowledge, like the collective birding knowledge, there hasn't been a nest in, you know, in Manhattan, at least in recorded history."