Science suggests we should stop using 'bird brain' as a barb / Birds have developed complex brains independently from mammals, studies reveal / Largest study of its kind proves 'bird brain' is a misnomer / Exquisite bird fossil provides clues to the evolution of avian brains / Blind birders in tune with bird sounds, call themselves 'bird brains' / Scientists pinpoint growth of brain's cerebellum as key to evolution of bird flight