Dear A.,
Welcome to the joys of things kids will try to taste.
It's not funny, at least not right this minute, but you will most likely laugh about it one day.
I guess it might make a difference if it's pet bird poop or wild bird poop. But either way, since she spit it out and you rinsed her mouth, I'm sure she will be just fine.
If she actually ate and swallowed a big handfull of it, it might be different.
My friend's kid ate and actually ingested a quantity of bunny poop. She was home with him alone at the time and completely freaked, rushing him to the ER, the whole bit. He was fine. He didn't choke and it didn't make him throw up or sick at all. They told her just to give him plenty of water and it would all "come out in the end". She was scared of of her wits, but we actually had a good laugh about the whole thing when it was obvious there would be no ill effects. Then, there was the neighbor kid who had a thing for snails.
If it was wild bird poop, you might just want to call your pediatrician, but it doesn't sound like she got enough of anything to harm her.
Hopefully you and dad having a panic attack will be enough to prevent her from trying to put weird things in her mouth again.
Best wishes!