Only infant dragons were immune to the call of an alpha, it was basic dragon knowledge. Too bad an undersized Night Fury was the exception to this rule. The real kicker: said Night Fury wasn't a dragon yesterday. Hiccup, just what did you get yourself into this time? Deviates at the start of the first movie.
Getting kicked off the legendary council was the bad news. The good news was that Articuno could finally satisfy his curiosity about those strange creatures called human beings. Unfortunately, the first human the ice-type ran into was a young boy with a red cap and a disobedient Pikachu.