So this is the state of the nest at the start of Monday.
Later this morning, Sooty comes in to admire her handiwork.
But what's this?
It is now about 3pm and a bluetit is poking its head into Box2. We haven't seen Lucy or Leo for some time and I have forgotten all about them. But this is definitely a bluetit at the entrance and the most likely bluetit to come to this box is Lucy. After all, she brought much of the nesting material into the box and probably still thinks it is her box!
What is more, she seems to be in the process of pinching some of Sooty's nesting material!
Twenty minutes later she is back for some more!
She has now removed all the easy stuff she can reach from the entrance hole, so now she goes into the nest box to collect and remove some more nesting material.
She has now been raiding Sooty's nest box for nearly 20 minutes. Why hasn't Sooty noticed?
Lucy is back for another load.
And another.
Having removed most of the fluffy stuff, Lucy now appears to be removing some of the grassy material.
She has collected quite a load here.
Eleven minutes later she is back for more!
My goodness! That's an enormous amount of stuff!
Nine minutes later she removes another large load. I wonder what she is doing with it. Is she just dropping it outside the nest box, or is she taking it to where she is building another nest?
This has been going on for over an hour - and Sooty doesn't seem to have noticed yet.
At last - Sooty has seen what is happening. I wonder what she will do? At the moment, all she seems to have is some minor additional nesting material.
If it were two bluetits, I would expect there to be a fight for possession of the nest box. This has happened many times in the past. But here the two birds are different species and I don't quite know what to expect.
This is the first time I have seen this type of behaviour in all the 24 years that I have been watching titmice nesting!
But does Sooty stop Lucy pinching her nesting material? Apparently not! This image was captured only two minutes after Sooty visited the nest.
A quarter of an hour later, Lucy is back again to remove another large load of material.
And more, twenty minutes later.
An hour and a quarter later, towards the end of the day, this is the state of the nest box.
What on earth will happen tomorrow?