Yep, I had ear mites in a Cochin once. It took a while to diagnose the problem and the poor guy was unbalanced, and spent his time casting his head back and forth and not moving. Now, not moving is not unusual for Cochin, but the kicker was s cheesy, pus-like substance in his ear. I could dig or squeeze it out. It took a long time to make a diagnosis, but as soon as I gave him regular treatments of ear mite oil he did get better. Unfortunately his ears were too damaged from weeks without treatment. I think the mites destroyed the balance centre in his ear canal and he was never the same. He eventually died.
So, oil smothers mites. Ear mite oil works but a daily treatment of olive oil, mineral oil, neem oil, etc certainly cannot hurt your bird. Well, maybe his feelings will be a little upset.