Roosting wrens....how many?!!

I have been away for a few days and last night, as I went out of the kitchen door to sort out some recycling, I happened to glance up at the wren nest wedged tightly against the wall behind the creeper. In the receding light I could count at least three beaks sticking out but it was clear from the shape of the nest that more birds were roosting within. My maximum count was twelve and this footage of wrens coming to roost communally is a fascinating insight into how small birds survive extremely cold temperatures at night. I love the quiet twittering they make as they greet eachother, although this isn't audible in this clip.