This video is called Dissecting Owl Pellets – Mr. Wizard’s Challenge.
There, old boxes were found. It turned out that these boxes contained many pellets, leftovers of meals of owls, raptors and other predators. Most were decades old.
Translated from the report:
The pellets were from ten types of predators. Most items were from barn owls (24 items). The long-eared owl was second (11 items). Then were six kestrel items. Pellets from other predators were only sparsely represented. 23 small mammals were identified in the pellets. The most special finds were water shrew, bicoloured white-toothed shrew, root vole, European pine vole and occasional finds of hedgehog, black rat and garden dormouse. In addition, a small number of birds and a small number of insects were found.
The complete report is here.