Small fast flying bird
This is really not a gardening question at all but I wonder if anyone else has seen this fantastically fast small bird in their gardens. This little bird appears every single year in May at dusk every single night. It never lands but flys acrobatically up and down the garden with such speed we almost can't see it. It dips and dives and changes direction from south to east so very quickly. It stays about 15 minutes and then dissapears. It is so fast we cannot see it to identify what it is. I wonder if anyone knows what it is! It comes every night until mid September and then it must migrate to somewhere warmer.