So, I'm starting to think none are. I'm 0/3 now for Wings or Birds of a feather. Each time a different reason, but Birds has definitely been acting up.
The first time, the charmed pet decided on its own to change targets. The last command i left him with was to fight Macha (the boss). I ran off to cure/heal, came back, it was fighting the other Neman.
The 2nd time, and I have a screenshot to go with it, is most interesting. After I my charmed/2hr'd Neman died, and I went to charm Neman #2, I failed 3 times in a row with +24/25 charisma. That in itself is probably just horrible bad luck, but when I went back to look at the chat log, it said I actually landed the charm.
Yet I was still getting beat down by a very NON CHARMED mob. So... what gives?