According to the Birdguides Newsletters one was seen in Suffolk on February 24th (a day before their first report of a Sand Martin)and at least two birds have been hanging around in that county until at least March 4th, with a bird over at Formby on March 5th. Mild conditions and strong south-westerly airflow seem to be giving them an unexpectedly early boost. They also noted that this year's Sand Martins were the earliest since 2014 with earliest sightings in March in most recent years.

Just had a friend message me about seeing two house martins in north Lancs today. Unless I'm mistaken that is incredibly early! I normally think of house martins as returning late March or early April. He's a reliable observer so not a mistake, but just another indication perhaps of how the climate is affecting our wildlife?