This morning there was a young house martin lying on the ground among bits of the broken nest which was high up on the gable.  The parents were flying around frantically but there seemed to be little we could do to help. Most fledglings are best left because the adults can often come and feed them but this is not so with birds that live mostly on the wing and do not come to the ground and having to find enough flies to sustain it would be very difficult and probably our bird seed and suet balls would be unsuitable.  Later our neighbour came round to tell us that their cat had brought it in and they were trying to revive it but it looked vey poorly so its prognosis is bleak.
While we were out I had noticed the sand martins on the beach swooping around and disappearing into the sand holes while the crows looked like sentinels on the posts above.  If by a remote chance a fledgling fell out of its burrow nest it would have a softer landing but be vulnerable to attack by gulls or crows which sometimes eat smaller birds.  Life is not easy for many creatures.

Edit.  The ?RSPB collected the baby bird so perhaps it now has a chance of survival.  The lady said she had rescued 5 in the last few days as apparently their mud nests are breaking up in the recent dry weather.