I have just been watching a starling carrying bits of stuff to the gutter of a house the other side of my garden wall, I assume it is nesting. It is the far end to the downpipe so won't block the guttering at all but I cannot help but wonder what will happen when it rains, does the poor hen bird and the chicks get a drenching from the water running down from the roof?

The nest is at the far right

Oy yes you're right! I hope they realize their mistake in time. When many kinds of birds nest for the first time they make all kinds of errors but they do learn and make better choices with later broods. Btw we had a Senegal Dove pair raise a chick on the top of a five inch diameter paint can (I measured it) on our bathroom windowsill.. successfully too! Amazed me.