I'm first! Yay! I'm never first!
I briefly considered a story about a book that eats an owl, but decided against it. Here's what I've com up with instead:
The owl stood on his towering perch of books, looking down over the expansive library that was his kingdom. He was old, so old, older than the grand library, older than even some of the most ancient tomes he guarded. That was his job, to guard these special books in one of the world's most secret locations. The books contained all sorts of things, from knowledge long gone, to things that no one ever knew about. Some were simply books, others were powerful, and a few more were out-and-out dangerous. There were scrolls, wax tablets, engraved rocks, charcoal-covered stones, diaries, manuscripts, blueprints, and real books of parchment and paper. The most recent thing in there was a leather-bound volume, a handwritten explorer's log from Borneo, set out in quill and ink. Even that had fragile pages of the particular brown-spotted yellow colour found exclusively in aged paper.
Old book smell was rife in the library, along with the distinctive smells of magic, mystery, and dust. It hadn't always been this way. Once, people had come often, so very long ago. The visitors were Muggles and Wizards, goblins and even the occasional centaur, anyone and anything. They were all drawn there for the information and to sate their curiosity, as scholars and researchers and discoverers in a Golden Age of wonder. The owl acted as familiar to all those readers, writers and keepers, back then. He was the magical animalian librarian, there to help.
He remembered them fondly throughout the centuries, as though they were yesterday. But good times rarely last, and after a while, only the humans came. Then it was only Wizards, and finally, not even they dropped in anymore. The library was forgotten, and its contents and protector with it. Perhaps it was better this way, for he knew the Wizards had a good reason for hiding it under the sand, as not even the most powerful books are immune to fire. But it was so terribly lonely! Often, the owl wished for even a stray adventurer or lost Muggle tourist, but alas, he knew this was not to be. He was a magical being, created to protect, and could sense approaching intruders or danger. It was how he could tell that no-one would be keeping him company any time soon.
His charges would be safe inside Alexandria's long-lost crowning glory for a very, very long time.