In past years I have seen house martins in the South Hams (Devon) as late as the end of October. One year there were still swallows near Salcombe, Devon as late as Dec 7th. Not living in the South Hams, I don't know how common this is i.e. this late. The return of house martins, swallows and swifts is something I welcome each year but sadly at this time of year we bid these migratory birds farewell before they fly thousands of hostile miles to lands with more plentiful insect food. With the Sahara getting bigger their migration routes are getting more and more hazardous. There seem fewer of these birds than there used to be, presumably as more die on migration.
Fare thee well little friends and see you again next spring when the cycle of life goes on, I pray. The return of these little fellows between early April to early May fills me with renewed hope and joy. I tend to have tears in my eyes when the swifts return. I pray I'll be around to see these return in the spring.