Having just recently seen Skottie Young's drawing of the Ozian field-mice for the comics adaptation of The Marvelous Land of Oz (I have the first issue, but haven't been keeping with the later ones, and might just buy the collected version when it inevitably comes out), I thought these mice might be a good topic for a post. The Queen of the Field-Mice, who wears a tiny golden crown, is prominent in both of the first two Oz books. In Wizard, after the Tin Woodman saves the queen from a wildcat intent on eating her, she and her subjects drag the Cowardly Lion out of the poppy field on a cart made by Nick Chopper. I'm not entirely sure why the poppies' fumes don't seem to have any effect on the mice themselves, but I guess the Lion wasn't really that far from the edge of the field. The queen tells Dorothy and her friends to call if they need her help, but when they actually do require assistance, Dorothy uses a "little whistle." That Baum never actually described the girl receiving this whistle is one of the more obvious gaffes in the book.
In Land, the whistle is said to be silver, and is in the possession of the Tin Woodman. He and his friends find a field-mouse village on their way to the Emerald City, and the Scarecrow hides a few of the mice in his straw, so that he can use them to scare away Jinjur and her stereotypically girly soldiers. The Queen of the Field-Mice also helps the party get through the illusions that Mombi throws in their way.
The Queen is not named in the Oz canon, but the Russian Magic Land books give her the name Ramina. In the apocrypha, she assists Eureka in David Hulan's Eureka in Oz, in which she reveals that she has a transportation spell provided by Glinda. She and her subjects also appear in Jeremy Steadman's Emerald Ring, and provide Trot and Button-Bright with a magic necklace, which provides light and sends Trot back in time.