one of my parakeets is scratching and rubbing his head on perches and toys constantly. he is approx. 4 mos. old.this just started a day or so ago. the other is scratching, but not as much. there are tons of little feathers everywhere, but they both look fine, except the one scratching alot is relentless with the rubbing and scratching. they are very active, ocasionally fussing with each other. is this molting behavior or possibly mites?