lokisantler

Hello everyone, I have a 20-something year old Timneh grey that's been acting a little funny lately. I've heard of parrots regurgitating food as a sign of affection. But I have noticed that my bird does it quite often. He bobs his head up and down and then this thick white stuff comes up out of his mouth. It does not look like a liquid. The stuff usually looks like white crumbs once it is dry and/or if he rubs his beak on the cage or perch. Nearly every time I am around him he does it, especially if I pet him (and sometimes he runs away while doing it, but he loves a good head scratch...). He also does it when I am not around which is what has gotten me concerned, because I've been seeing that white gunk on his cage from time to time. His behavior hasn't really been out of the ordinary, but he IS a finicky eater, although he kind of always has been. Any ideas? He's never been ill before and I'm hoping he is not now. But should I contact a vet about this?