Scientists have made an unusual discovery inside fossilised dinosaur droppings: a bird feather. These ancient droppings are 66 million years old. It is thought to have been left by a Tyrannosaur. Seeing a feather in such good condition is very uncommon. It provides a clear glimpse into what the dinosaur ate. The meal included a bird, as shown by the feather. This might help explain how some birds survived the mass extinction. The details appear in a newly published study. It gives us a snapshot of ancient predator-prey interaction.