Could be slugs eating your Gerbers. Put some kind of board, rock, upside down pot (dark plastic) or other hiding place on the ground near your Gerbers, look under it in the early morning and see if slugs are there. If so, get rid of those particular ones and then put out Sluggo or other "treats" for them.

Or you can watch for slugs under things after watering in the early evening when the area is shady. Water, wait a bit, then check.

I have been watching my gebera daisies to see what was eating the petals...I just have the centers left on every bloom. The plant leaves look fine.

It is the birds. For some reason they are picking the petals off and flying off with them.