My bird is wheezing, What could it be?

 
My bird is wheezing, What could it be?
I noticed today that my bird was wheezing a little bit after I got home from work. He lives in a good environment, clean cage, healthy. I have had him since he was 9months old. He is a goffin cockatoo and male.

I plan on taking him to the vet but I just want opinions before i take him in tomorrow.

His wheezing sounds like a whistle in his nose. I can hear it from a couple feet away.

He has been picking at his nails a lot lately. I try to give him new toys so he doesnt pick.

Before i take him in, does anyone have any idea what it could be??

The wheezing stops after a while.
He could have a cold. My sisters parrots get them sometimes.
I think it could be a cold or something worse..... Make sure you squeeze him in to the vet as soon as you can. Play it safe dont risk your bird becoming seriously ill.... GOOD LUCK :)