The starling which had been hovering opposite the entrance, then backed off and flew onto the roof of the box again.
Babe continued to display and you can see that her beak is open, so I presume she is making a bit of a racket too - presumably calling for reinforcements from Ferdinand (we have decided to call the male Ferdinand - have you noticed that he has lost his tail?)
By this time the starling is on the roof and peering aggressively into the box from above.
Babe still has her guard up and her beak open!
There is still no sign of Ferdinand, but one senses that the starling is losing interest in this battle. I wonder if it would have been different if there were young chicks in the nest box?
I think he flies off at this point as this is the last shot of him around the box.
Twelve seconds later, Babe is starting to relax again. She clearly feels that the threat has passed.
Whether Ferdinand had anything to do with it or not, I do not know but it is nearly a minute later that he appears in any of the pictures.
"Are you alright dear?" - stupid bird!
"A fine lot of help you were!"
Of course we can never know what actually passed between them ...
... but for the rest of the day, Ferdinand was strangely attentive, and hung around the box quite a lot whether Babe was inside it or not!