Still no swallows (barn) - NOT amateur radio

Last year I saw just 2 all year.  It is already April 28th and I have seen none at all. In the past I had definitely seen some by the middle of the month. Perhaps it is climate change or fewer nest sites? 

The next milestone will be the swifts arriving. They are usually a common sight and sound by mid-May. Will they be here next month? 

There are some swallows around, but I suspect there must be far fewer this year.

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