I've had an e-mail from Ian Burgess saying that he had a Swallow yesterday from his garden in Penrhiwllan, heading west and wondering what the latest recorded date was in Ceredigion (Ian wondering, not the Swallow).
According to Birds of Ceredigion there are at least four December records, with the latest on 17th Dec 2001. In most years they are recorded well into October, and not unusually into November.
I suspect that, like others, I search eagerly for the first migrants in spring, yet in autumn they tend to slip away un-noticed. By the way, I had another Chiffchaff in Llanilar today.
There is a table giving earliest and latest dates of summer visitors in the annual Ceredigion Bird Reports.