Chattering moustache

There's one outside of our caravan, in and above the hedgerow (sometimes several metres). Its got a mate and when she appears the moustache fluffs out at a ridiculous angle. What she sees in it we can't imagine but she seems to have chosen one of its nesting attempts. So, hopefully, we'll see a brood of Whitethroats popping out of the hedgerow before the end of this month.