Plumage in the Cretaceous period, which holds important evolutionary clues, is notoriously difficult to study due to the poor preservation of details in compression fossils. Fortunately, however, two ancient bird wings trapped in Burmese amber 99 million years ago have been found in which feathers have been preserved in stunning detail. The samples have allowed Lida Xing of the China University of Geosciences in Beijing and colleagues to make detailed studies, for example using synchrotron X-ray micro-CT techniques, to reveal the first examples of several physiological structures – including follicles and feather tracts – that until now have not been preserved. The feathers are likely to be from hatchlings of enantiornithines, a group of extinct flying dinosaurs.