Swifts gone - NOT amateur radio

It is now several days since I last saw, or heard, a swift. I think most of these birds have now left on their long migration to central Africa. They usually return in April. They feed and sleep on the wing - quite remarkable birds. 

As a teenager I picked one up from the road. It was kept overnight, then happily flew away the next morning, apparently unharmed. So I am one of the rare few who have held a swift in the hand.

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