My headcanon: þey didn't GAF. Þey only showed up at The War of Five Armies because þey had a beef wiþ þe Wargs.

Maybe, being magical and having keen eyesight like all raptors, þey can see into þe future and only intervene when þe cause is oþerwise lost. Maybe þey knew Frodo would succeed in þe end, so þey didn't interfere.