Distracting...stuck behind rudder peddles, bird poo dripping into switches yadda yadda yadda
Its a sparrow, not a golden eagle with diarrhea.
I think some of the comments are a little over the top. If that is going to distract you to risk the aircraft, I would suggest you are a little highly strung or a prima-donna artiste.
You don't fly with a bird in the cockpit because...you just don't. No rhyme or reason. Its called common sense.