In the series of books about Harry Potter, J.K. Rowling described not only the adventures of the young wizard Harry Potter, but also various magical creatures, including the snow-white owl, named Hedwig. The most interesting thing, that the owl did not carry the mouse during the movie, but the letters... because... it was specially trained by Julie Tottman (watch a Youtube clip).
When you arrive at the VU Zoological Museum, you will be able to see the same kind of owl, and for now you can read more about it.