I have seen one shrike occupy himself for hours in sticking up on thorns, a number of small fishes that the fishermen had thrown on the shore. The fishes dried up and decayed.
“If you were a medieval scholar reading a book, you knew that there was a reasonable likelihood you'd never see that particular text again, and so a high premium was placed on remembering what you read. You couldn't just pull a book off the shelf to consult it for a quote or an idea.”