Where has she been all of Jeremy's life?  Just when the young hopeless romantic of a crow is ready to give up on finding a girl, she literally bowls him over in the closing scene of the movie.  A tiny bit clumsy herself, though not as bad as Jeremy is, she demonstrates a similar passion for string, and any romantic consequences (and she's something of a giggler)!  We never do learn her name.  She's only credited in the movie as the "Miss Right" Jeremy's been looking for.  And as the movie ends, we see her and Jeremy flying off together with their string, romance presumably in the offing!

Quote: "Excuse me, pardon me" (*giggle giggle*)...

Origins of the character: In Robert C. O'Brien's book "Mrs. Frisby And The Rats Of NIMH", while "Miss Right" is never mentioned (by that title), nor seen, she is mentioned in a conversation between Mrs. Frisby and Jeremy:

Mrs. Frisby: "Why are you interested in shiny things?"

Jeremy: "Well, really, I'm not.  At least not very.  But I have a friend who likes them, so when I see one I pick it up."

Mrs. Frisby: "I see.  That's very thoughtful.  And would the friend be female?"

Jeremy: "As a matter of fact, yes.  She is.  How did you know?"

Mrs. Frisby: "Just a guess."

In the animated sequel: There is no sign whatsoever of Miss Right during the entire sequel...nor any mention of her.  Nor any sign that Jeremy ever stayed with her or had any offspring with her.