Are we to late?

I spent the day discing up land damaged by last year wetness and have been fallow with in the crops we did get in. It has been a slow and very bumpy day trying to get rid of the ruts. While doing this I was accompanied by a swarm of swallows feeding on the flies. This made me think about the date and the number of nests still with unfledged young. The last part of the mill at Groves is still standing awaiting a nest of three swallow chick to leave before the wrecking ball can re start work. At home there is a nest in the lean to and up at the yard where Miller lives this little family still await take off! Just how late can they afford to be fledging and still make it to Africa to over winter?
Trust all is well with you one and all ;¬}