I have been making nest box observations every two weeks, opening a hinged door on the side of the box and looking in. On the last observation, on May 25, I saw five nestlings looking back and staying very still. Yesterday I saw one of them has fledged and was out on a tree branch next to the nest box. Today there are two of them there on the branch and two heads poking out of the box entryway.
My question is: Is it safe for me to go open the nest box door and look inside? I don't want to take the chance of disturbing the birds in the nest that have not fledged and scare them out on to the ground.