Not the case, as it turns out. Now that Janice has had a chance to chat with her and catch up on things, we found out the awful truth. One time when she was over here, she let the cats out onto the balcony, which they love and which they're not able to jump down from. When she came back, she found bird parts scattered about our dining room: the inner predator had surfaced in at least one of our cats (probably Feanor, given his past history), with tragic results for at least one bird (probably a goldfinch, again given past history). She heroically cleaned up the mess, but wasn't able to find the little bird's feet. So either they're somewhere inside one of our cats, or we'll come across them at some point, way back behind some furniture or under a bookcase.
Cats. Always an adventure, and the unexpected more often than you'd expect.