Thanks for using JustAnswer.com, I'm Dr. Dan and I'll try to help you.
Is the skin associated with the bald spots flaky, red or itch?
Thanks for the information.
This is not the typical spot for mites and typically mites cause reddened skin and flaky skin. I would probably have the spot checked by a vet just to be on the safe side. I would like to have a professional look at the black spots. However I wouldn't be surprised if the black dots are new feathers coming in to replace the old one. If you look too closely then most owners mistake the normal featherless area between the lower jaws behind the beak as abnormal feather loss. This area is normally bald or almost bald. It's a good idea to have it looked at but my suspicion is that if you are patient then the feathers will return on their own. If the feather loss spreads then it's definitely vet time. I hope this helps, best wishes.
Ok thank you for describing the area more carefully. I have worked with many Grey's before. Birds don't typically grieve but they do very much get a security from their flock members. When their flock numbers decrease they feel more vulnerable and less protected. This will increase their stress level and decrease their security. This is sounding more like feather damaging behavior.
What is in the best interest of your feathery friend is still to see a bird savvy vet. Make sure you ask if this vet has dealt with feather loss before. A vet is needed to take a detailed history and examine your bird to make absolutely sure there is no complicating medical issues. Then your vet can help you with creating a plan to introduce more security and decrease stress in your birds life. I can tell you these cases take a lot of time, patience and understanding on your part. There is almost never a quick shot, pill or fix to take care of this. If you want to try things on your own first, a good place to start is by purchasing the following things Birds for Dummies© written by Brian Speer, DVM, and the DVD called Captive Foraging© by Scott Echols, DVM. Here are a couple of other free resources to give you an idea about feather damaging. http://www.harrisonsbirdfoods.com/featherpic.pdf
http://birddr.com/pages/CareSheets.php (when you get to the second website click feather plucking) These items may get you a start but are much more effective if guided by a vet. I hope this helps, best wishes.