Here is another example of a couple of bluetits doing a swap. There is already a bird in the nest box when another comes to the nest box hole.
The bird inside crouches down to keep out of the way ...
... and the outside bird enters the box.
Here you can see the outside bird entering the box from the inside camera. See how the inside bird has positioned itself on the floor of the nestbox so as to be as much out of the incomer's way as possible.
Directly the exit hole is free again, the inside bird is off like a shot!
This rather confused image is all we managed to catch of the bluetit leaving the nest box.
Of course, the 64,000 dollar question is this! Which was the male and which the female?
Later in the day we caught this sequence.
A GT lands on the roof of the box and has a look inside.
However, there is already another GT inside and she looks as though she is ready to repel boarders!
Ten minutes later the same thing happens again.
Here is a great tit coming in to land.
Here is the inside bird striking distinctly unwelcoming attitudes.
This picture was taken only 2 seconds after the last one. I'm not sure whether it is coming or going. Most odd!