Common swifts back in Newcastle on Tyne yesterday, screaming party of 4, and a bird returning to the regularly used box at my partner's place. She confirmed this morning that the other recently opened up box beside it had been occupied by the local tree sparrows..
@gerald762 for comparison with Huelva, I saw my first common swift this year on 23 March in the Alentejo, a week later than last year (16 March) when I had my first near Tavira - later arrival not surprising given the wet spring this year.