Natures visitors is the perfect forum for this.
A pair of House Martins have raised a brood so close we can almost touch them.
I think there are four chicks in the nest and they fly but come back to the nest to be fed by the parents. I suspect that they are just building thier flying strength ready for the big migration to Africa.
In the picture you can see some of the chicks and a parent on the nest, and the white blur is the other parent queing to feed the chicks.
Both parents back, chicks feed, both parents gone, less than 3 seconds! I had to be quick.
Mike