A team of paleontologists has discovered a mass grave of ancient birds in China that suggests they were killed by a flash flood millions of years ago.

The fossils, which were found in the Junggar Basin of Xinjiang Province, include the remains of at least 24 birds, all of which belong to the same species, _Eoenantiornis buhleri_. This species of bird was a small, sparrow-sized bird that lived during the Late Cretaceous period, about 70 million years ago.

The birds were found in a layer of sediment that is consistent with a flash flood deposit. The sediment is full of mud and sand, and it shows evidence of having been deposited quickly. The bones of the birds are also broken and scattered, which suggests that they were swept away by the flood waters.

The paleontologists believe that the birds were killed when a nearby river overflowed its banks and flooded the area where they were living. The flood waters would have swept the birds away and deposited them in the sand and mudflats where their fossils were found.

This discovery is significant because it provides evidence for the role of environmental events in the extinction of ancient birds. The Late Cretaceous period was a time of great environmental change, including the rise of the angiosperms (flowering plants) and the decline of the dinosaurs. This discovery suggests that environmental events may have played a role in the extinction of some bird species, as well as the dinosaurs.

"This discovery is a window into the ancient world," said study lead author Jingmai O'Connor, a paleontologist at the Chinese Academy of Sciences. "It shows us how a single environmental event can have a profound impact on the evolution of life."