Fluffy is having her usual afternoon siesta sitting on the eggs.
(We always wonder how the eggs are supposed to know when incubation has started. In spite of the fact that the early eggs get more of this treatment than the others, they all hatch within about 24 hours.)
Barney comes to pay her a visit.
We think from her reaction that you can see in the image below, that he must call to her.
She obviously perks up and presumably replies in some way.
Barney departs, his mind set at ease. All's well with the world.
But Fluffy soon drifts back to sleep again.
Incubation must be a very boring occupation for a bluetit.
Well, it may not be clear to us whether Fluffy has started incubating, but Barney clearly thinks she has. Here he comes in with some food for her.
Here, a couple of hours later, he's back again. To be fair to Barney, Fluffy has left the nest three times in the interval, once for 18 minutes, so perhaps it's not clear to him whether she's incubating or not either!
If she has started, she may or may not lay another egg tomorrow. However, if she does, it will be her last for this year!