Rare feather unearthed inside dinosaur coprolite offers clues to bird survival

A paleontologist uncovered a remarkably intact feather inside a dinosaur coprolite from the Hell Creek Formation in Montana, marking the first feather ever found in such fossilized feces. The find emerged during a routine collection of fish fossils, and subsequent micro-CT analysis revealed several feathers, fish scales and leg fragments of a small, extinct bird. While the exact producer of the coprolite remains uncertain, its size and contents point to a large predator like Tyrannosaurus rex or Nanotyrannus that had swallowed a hesperornithiform bird.

The feather belongs to an aquatic, flightless bird closely related to modern birds, and its preservation may illuminate why crown-birds with fully developed plumage survived the Cretaceous-Paleogene extinction event. Lead author Jingmai O'Connor calls the result a “call to action” for scientists to scan other coprolites for hidden soft-tissue fossils. The study appears in Current Biology and could prompt broader investigations into ancient food-web interactions.