my mouse making a chirping sound

Question
Dear Tamarah
One of mice (I have two females) has started making a chirping noise when I pick her up. Her tummy looks a bit fat but I don't think she is pregnant because I have had both mice for about 5 months.She is eating well and drinking well and seems healthy in every other way. It just started tonight when I picked her up. I do not pick them up by the tail but gently scoop my fingers underneath their bellies.

Answer
Hi Lauren,

Is the chirping sound only when you lift her, or while you are holding her, too?  Does she ever make the sound when you are not playing with her?  I would keep a close eye on her to determine what is causing it.  Chirping could be a little squeaking sound she makes to you, either because she is uncomfortable being picked up or was possibly just surprised.  Check her belly and feet for any little cuts or scrapes that could be tender.  If it sounds like a clicking sound, not a squeak, it could be a sign of respiratory irritation.  This could mean an infection (though I'd watch her more to see if she continues to chirp or if it's just when being played with), or a coughing/sneezing from an irritant in her cage or in the environment.

Without knowing more about the sound, when it's being made, and where it's coming from, I can't quite pinpoint the cause.  If you're concerned that she might be sick, bring her whole cage with her in it to your local vet that sees pocket pets - they'll be able to quickly identify the cause and get it fixed - whether it's a one-time thing from the way she is being lifted, or a sign of a respiratory infection that would need simple antibiotics in the water.

It'd be a good idea, too, to watch the other mouse for any similar signs in the meantime.  She might be able to give you some clues!

Best of luck!
-Tam