As you all know, being fans of David Attenborough, owls regurgitate the indigestible bits of their (mainly) rodent prey in the form of pellets. So, if you dissect a pellet you can find what they have been catching by examining and identifying the skin and bones of various species. And, if you are so inclined (ie, because there's nothing on TV, your marriage is on the rocks or you are doomladen from watching CNN), you can pick through the bones and decide if your local Tyto alba has been noshing wood mice or common shrews or short-tailed field voles. But to make such specific identifications, you have to examine the teeth, ie, pull a tooth from the lower jaw and study its profile.
My young naturalist friend from next door has been doing just that (I took her and mum today to a Barn Owl nest with young, and she's hooked). She's been at it for a while now: ripping out teeth, examining them through the magnifier, comparing them with the ID chart, and then announcing the identification. Stunning.
Me, I am just looking at the TV guide to see if there's something I can cope with that doesn't involve pulling teeth. Maybe a cookery programme about how to fillet haddock.