changing feather colors

:? I bought my first budgie 6 days ago! One reason for choosing him/her was the beautiful, dark blue tail feathers with black shaft. The next day, the budgie's top tail feather was yellow! I thought maybe pet shop girl caught the wrong bird! Then, the next day the tail feather was dark blue again! Today the top feather is back to yellow with a white shaft. I had my husband confirm this to make sure i'm not crazy!
Is this common? Are these birds part chameleon? Is this a sign of stress that I should be concerned about? Thanks for any advice, this is all new to me and I can't find anything in my books about this...
Holly in North Carolina

 

Hi First off congratulations on your new bird. I have to admit i have not heard of birds changing there feathers apart from young birds who have not yet got there adult feathers,

I do know is that it depends on the position of the feathers at the time as some birds have there large flight feathers on there wings under the tail feathers then the next time you look they are over the tail making it look like they have changed colour.

When a bird is stressed they usually start plucking there feathers so this is really nothing to worry about.

So you have a picture of your new bird.

Mike