This shot was taken 6 days later and as you can see, the nest box is as full as it was in the first picture.
This time we are thinking that Sally is becoming serious. She frequently does nesting wriggles across the floor of the box where she plans the nest cup to be. This is always as far from the entrances hole as she can get in order to avoid predators.
Incidentally, we are calling the pair of bluetits using this box Sally and Sam.
Here is another wriggle. The frequency of nesting wriggles increases as the nest nears completion.