Swifts arrive - is summer here?

We get a lot of birds in the garden, but it is around this time of year that the swifts (or are they House Martins?) return from wintering in the tropics (all right for some, eh?). And that has now happened with mornings and evening punctuated by gaggles of very fast birds flitting around the skies gobbling up airborne insects. Difficult to see as they move so fast and change direction quickly, the main clue to their proximity is the high pitched "chittering" sound they make. They don't seem to nest around our buildings, preferring our those of our neighbour's, but we don't take that as an insult.
Anyway for Mary the return of the swifts makes her feel summer is almost here. Bring it on.