Leaving Home

I got back home after work today to find that the housemartins have finally taken flight.
They have been flying in and out all evening and sometimes clinging on to the brickwork while waiting for one of the others to make room to get back into the nest.
I'm not entirely sure how many there are at the moment, there are at least 4 birds and possibly 5, they don't all stay still long enough for me to be sure.
There is an extra photo of them clinging on near the nest.