Allotments 4 All

I have a blue tit sitting on eggs [I think], anyway she is sitting on a nest in a box in the garden.  She does not seem to leave it and Father bird does not appear to be flying in and out.  So how does Mother bird get fed?  I  am worried in case something has happened to Dad.

If she was hungry she'd soon desert the nest so don't worry. She won't sacrifice herself for the young.

Thanks for that.