On my way home from errands in town I stopped for - omg, must have been an hour! - at a couple of puddles in the trail around the fortress. I just nestled next to a tree a few yards away and snapped away as one species after another came to bathe and drink - blue tits, great tits, chaffinches, siskins, a grey thrush, and this little one which I'm not quite sure of. Is it a willow warbler or a chiffchaff? I'm pretty sure I heard some of each in the vicinity, but while bathing this one wasn't singing.