Oh they do make a horrendous mess

. If you stand still for a minute they get you too

But they are truly worth it Bazzais. They are so tiny but they fly all the way down to South Africa (where they seem to roost in shrubby trees in large numbers, a bit like starlings here (or so I saw in a tv documentary

)). They stay there to fatten up on all the insects down there then magically they fly all the way north again, right back to the place they were hatched. Wonderful

They work so hard too raising three nestfuls of babies and catching all those flies we hate to feed them.
It's always a relief when they fly south in September and the clear-up can begin. Suddenly you can hear all the other birds which have had their songs drowned out by the swallow babble. The cat gets some peace from being dive-bombed every time she snoozes in the sunshine. But then when they come back in Spring they are so welcome

I love the way they don't give a tinkers about humans, don't fear us, barely notice us, we are just there to inhabit the buildings they need for nesting