Swifts - NOT amateur radio

Usually I see my first swifts at the end of April. This year, it was May 10th before I saw them and even that was in South Devon.  These are migrant birds and I suspect numbers are down. They have been seen for some weeks, but I had not seen any before yesterday.

Once I see them, they appear ubiquitous, screaming on the wing. Usually they are the most common bird seen in the spring/summer sky. They are here all May and June and then you just notice they have gone until next year. The skies are quiet.

See https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/swift