Heard on the news this morning that they are migrating early - ours seem to have gone. Much to Theseus' delight, I might add, as the front doorstep has been covered in bird poo several times a day! But I have enjoyed watching them swoop around.
Found this article when I was trying to find out, and realise that we were lucky..!
www.dailymail.co.uk/news/article-2034766/Couples-shock-wake-500-house-martins-perched-home.html
Nicola Sturgeons husband pleads guilty.
What are you avoiding doing in this heat?

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ours are still here flying about, must be at least 50 swooping about...although does seem to have quietened off a bit this last week.
I had only just finished the exterior painting..all lovely frersh magnolia...! when the inevitable happened! tut! yes bird poo! streaked down my lovely painted walls....fortunately our lovely weather soon washes it off 