As I was checking my Internet, I sensed some chirping and looked up to find a swallow (I think) sky-diving me. He and his mate are building a nest. I can’t hear, or see, any nestlings but the parents chirp into the nest. (I wish I knew more about bird behaviour.) When one arrives, the other flies off aiming for my head – very aggressive little creatures. If I’m very still they disregard me.
It’s taken me two days to get this photo. It’s great to see them in mid-air, changing places, but I didnt manage to click that. So, the boatyard is full of men and women preparing their sail-homes, and in this corner, about six feet away from my desk, these two are busy with theirs. Good luck to them.
Palo Stickland 
That looks like a swallow’s tail. If they have chicks they will be carrying insects to the nest, though the nestlings might be too small to see yet if just hatched. when they are due to fledge they are too big for the nest and how they don’t fall out is a mystery. It’s possible they are still preparing the nest for a complete set of eggs before the female sits down to brood – because she can only lay one egg at a time they tend to wait until all have been laid and then incubate.
Thanks, Sue. I knew you would know.