Bearded tit

Along with her girlfriend, this is one of the first bearded tits ever recorded in inner London (the majority of male hipsters in north-east London notwithstanding).

This explains the small crowd of twitchy bird nerds in fluctuating attendance next to the reed bed they chose next to the Princess Diana fountain in Hyde Park; and, in turn, this explains the mass of bemused expressions on the faces of tourists passing by. Although the one who opined that we were all "sad" is a twat, obviously.