We had some young great tits in our nestbox, saturday they were still chirping, but saturday there was no sound coming from the nestbox anymore. ( and i dont think they were old enough to leave the nest). So we decided to take a look and we saw 1 young great tit in the nestingbox. He doesnt make any sound and sits still. We thought his brothers and sisters did already leave the nest so we did leave him alone. Today(tuesday) we decided to check if it was still there. And it was. What do we have to do now, i have no idea whats going on?? I wanna help the chick if possible. And i dont see the mother or father flying in anymore. What is happening?