I’m worried about a baby blue tit that’s not fledging, it’s well overdue, I think it might be stuck in the nesting box. I thought they’d died early on because when they first hatched I could hear lots of noise and there was lots of feeding activity and then it all went quiet but the parents were just sat watching the box. I noticed some long black tape (like cassette tape) which I thought might be blocking the entrance, I pulled out as much as I could but had to cut it and 1 baby started chirping again and parents began to feed again… fast forward 4 weeks and they still are and I can see the baby is quite large and feathered but not coming out. I’m worried his legs might be tangled in tape. I don’t know whether to open up the nest box and attempt a rescue?