My bird has been tired lately - he has a lot of pin feathers on his head (and lost a few larger feathers while playing recently) so I figure he's moulting (?). He has also just been preening constantly.
It seems like when he's not doing anything, he fluffs a bit and sits with his eyes open, moving very little, alternating legs.
Sometimes I'll let him out of his cage at these times and he'll fly around, sing, play with a mirror, or show affection to me on my shoulder. When he goes back to his cage, he'll continue this cheerful, playful mood for a while and then it's back to the fluff.
I've often read that a fluffed up, lethargic bird is sick. Could it be that he's just getting old (Approaching 9 years?) and this is how he is when he's bored? If it's quiet and I put on music he'll respond to it for a while, but he'll flip between having fun and just doing nothing in this puffy state.
Do budgies who are moulting tend to be like this? It seems like this molt has been going on for weeks/months now, is that relevant?
I would recommend a vet trip. As bad as my bird's have moulted in the past, none have ever seemed to be effected quite as bad as you describe. It is quite possible that an older, molting bird has caught an illness.
He came down from Heaven unto this earth below
He came down from glory and praises untold
He came down to man fashioned in their way
He came down to rescue, He came down to save
How lucky are you to have shared nine yeas with your budgie you must be taking excellent care of his well being .
As he is an older budgie who is going through a pretty tough moult by the sounds of things I agree with Randy that a wellness check up would be a great resource for you at this point. Also perhaps obtain some egg and biscuit mix this is a huge help for growing in new feathers and tiredness. Probiotics and apple cider vinegar with Mother in it are also a great tool for keeping a birds system in top condition. Please let us know how the visit goes and we would love to see a picture of your budgie if at all possible .