A feather preserved in a dinosaur dropping, found in 2016 in north-eastern Montana’s Hell Creek FormationO'Connor et al. A bird that was eaten and partially excreted by a dinosaur 66 million years ago has left behind the best-preserved feathers ever recovered by scientists from dinosaur-age rock. This pushes the evolution of feathers, like the ones on modern birds, back by 10 million years and may tell us more about why most birds didn’t survive the post-asteroid mass extinction. “This is the best feather we’ve ever seen in a Mesozoic [252 million to 66 million years ago] deposit,” says Jingmai O’Connor at the Field Museum in Chicago. “[It’s] like a feather you could pick up off the ground.”...