Yo Sascha, like your bird Video.
But to be honest, I did not really like that you disturb them in their birdsnest.
Yust an Idea, place a web cam inside before they get in.
Cheap products, even ready sets with solar e.g. are availabel on ebay.
i use a little endoskope cam to have a view inside the nest so its not a big deal for the birds. the little birds thinking it feeding time or mnot even notice that and the bird moms thinking its another bird watching into the nest to see if its occupied or not. that happened more times a day and you can hear it when she is yelling around
We are about 4 weeks behind up here. Not seen any fledged birds at all yet. Adults are feeding in the garden and taking stuff back to the nests.