Scientists have discovered exceptionally well-preserved remains of an owl that lived in Germany around 47 million years ago, potentially changing our understanding of the evolution of these birds. In the ancient animal’s stomach, researchers found the remains of an insect, suggesting that the ancestors of modern owls were probably active during the day. The discovery was reported by the German publication GEO, citing a study published in the scientific journal Current Biology.
The fossil was discovered in 2025 at the Messel site in Hesse, which is included on the UNESCO World Heritage List. Scientists from the Senckenberg Research Institute in Frankfurt established that the remains belonged to a previously unknown owl species named Masillastrix blattophaga.
The bird was only around 12 centimetres long. Despite its immense age, the skeleton is almost completely preserved, with the exception of the skull. Even parts of the feathers on the wings and tail have survived – an exceptional rarity among fossils this ancient.
The greatest surprise, however, turned out to be the owl’s last meal. In the stomach area, scientists discovered the remains of a cockroach with iridescent greenish-blue wings. An analysis of the distinctive veins in the wings confirmed the insect’s species. Just a few metres from the fossil, the researchers found another, significantly better-preserved cockroach with similar characteristics.
The discovery is important because in cockroaches and some other insects, such iridescent colouring is associated with activity during daylight hours. This gives scientists reason to assume that the ancient owl also hunted during the day.
Additional evidence comes from the structure of its wings. Unlike modern nocturnal owls, which have specialised feathers for almost silent flight, the ancient bird did not possess the characteristic adaptations for moving quietly through the air. The bones of its wings also differ significantly from those of modern members of the group.
„It is still unclear exactly when, in the evolutionary history of owls, the transition from a diurnal to a nocturnal lifestyle took place,“ explains Dr Gerald Mayr of the Senckenberg Institute.
According to the researchers, the new data show that owls probably became nocturnal hunters sometime between 47 and 34 million years ago, during the Eocene. The oldest known owl fossil with wing proportions characteristic of modern species was discovered in France and is around 35 million years old.
Scientists stress that the find does not conclusively prove when nocturnal activity emerged in all owls. It does, however, provide exceptionally valuable information about the lifestyle of their distant ancestors.
The discovery also demonstrates the unique conditions for fossil preservation at the Messel site. Thanks to them, tens of millions of years later it is possible to study not only the bones of ancient animals, but also their feathers, their last meal and even details of their behaviour.