Confused Chiffchaff?

I was down by the quayside at Newport this morning, dropping off some tourist guides to one of the pubs (in the hope some visitors of the human kind are still around) and heard a Chiffchaff in the shrubs behind the car park.
Chiffchaffs often hang around late and some even stay for the entire winter, but this one was singing. Maybe he was confused by the mild weather? It's by no means sunny but it is fairly mild for mid-October.