Hi all

Just looking to get trees pruned and a fence put up so decided to take the
bird box down first.
The hole has been over enlarged so we haven't had any visitors there for a
while.
Climbed the ladder and peared in to see a tit of some variety staring
back!!!
Somehow they've snook in without me noticing and started nesting - I do keep
a reasonable eye on the bird life, so I'm suprised they've managed to build
a nest without me noticing.

Now to the questions:

1 Will it scare off the bird if the tree, a silver birch, is seriously
pruned (probably need chain saws!)
2 How long will it take for the eggs to hatch and the babies to flee the
nest if I decide to wait?
3 Is it likely I will have scared it off anyway having put a ladder up
directly below the box and peered in?

TIA

Phil