We believe the roosting great tit is female because of her behaviour inside the box overnight - and in the following morning!
She normally leaves the box for the first time in the morning soon after sunrise - which at the moment means about 7.45am.
Here she is returning to the box for the first time a couple of hours later.
The first thing she does is to clean the box of any droppings she may have left overnight.
Here you can see her with one in her beak. She will probably only have left one or two and her first job in the morning is to get rid of them.
The next two images were taken at the same time - one showing a great tit outside the box, ...
... and the other showing the inside bird. Both were taken within a second of each other.
This time the bird inside the box is clearly looking aggressive. Not only is her beak open but she is also spreading her wings.
Does this mean that these two birds are not a pair? Have great tits not yet paired up or is this a third bird wanting to get in on the act?
Fifteen minutes later we have another pair of shots.
No sign of any aggression here.
I suppose the birds will work things out eventually!
A final shot of our fat feeder.
One of the things we like about bluetits is that they are relatively friendly with each other. They are not flocking birds but after the chicks have fledged, families seem to stay together for quite along time.
I'm not suggesting that this group of 8 bluetits belong to one family - although of course they could be - but I wouldn't be at all surprised if quite a few came from the same nestbox!
Click on the image for a bigger version.