Hi Everyone !!..I am new to the forum

Greetings slslady and Chico! Welcome to the forum!

I would be surprised if Chico is wild from what you describe. If he is really tame with you, even after 2-3 months, then from what I understand, chances are he was a hand-fed bird/tame bird to someone at some point. The fact that he arrived through a window and didn't want to leave also implies that he is used to being in the human world. I don't think a wild bird would be very likely to do something like that.  Personally, our QP does not talk, and while she does make some exotic noises that she probably wouldn't have picked up in the wild, she uses predominantly natural sounds to communicate-- so that is definitely possible in captivity.

As far as his aggression goes, this is very typical behavior for a parrot who has formed a strong, exclusive bond with one individual. Chico sees you as his mate, and he is being protective/possessive of you when others are around. He wants your attention as much as possible and is not okay with others getting it instead of him. Try having the others give him treats, and have them try spending some time just talking to him without trying to interact too much, and perhaps dial back your own affection with Chico a bit.

Try not to react in an animated fashion when he attacks the others, but make sure that he knows that you are not okay with it. Give him some stern eye contact that is in clear contrast to the eye contact that you typically give him when he is being good. When he does *anything* that could be construed as friendly or even neutral to the others, praise him very clearly. As a rule, you want to respond with positive reinforcement whenever Chico does something desirable, and then provide stern eye contact and subsequently ignore him for a little while when he does something you would prefer he didn't do.  You can also put him in the cage for brief (no more than 5 minutes--they forget quickly) time-outs, but you want to be careful there, because you don't want him viewing his cage negatively.

Changing this kind of behavior requires a lot of patience, but it can be done. Initially, our QP Cupcake was very protective of me, and aggressive towards the others in the house, but now she has a bond with all three adults in our house, exhibits essentially no jealous behavior, and ultimately seems to love the flock dynamic of having everyone together. But it took months for this change to occur.  

There's no way to physically determine the sex of a Quaker parrot. You can have him DNA tested at the vet for $50 or so. And obviously if "he" ever lays an egg, that would clue you in that he's a she... Otherwise, behaviorally they are similar enough that there is no reliable way to tell the difference between genders.  I don't know much about the signs of aging in Quaker Parrots, but I would guess that they too are not very consistent.

Good luck and feel free to ask any other questions you might have! Everyone here is happy to help!

Welcome slslady and Chico! I have to agree with Aaron that it is unlikely that Chico is wild.  A bird that comes into adulthood in the wild is going to be exceedingly hard to tame, and is not likely to pick up human language so easily. He could have been on his own for a while, though. I had childhood fantasies about a bird just up and landing on my shoulder (too much Disney for my own good), and would have loved to have one fly into my house!

Welcome to you and Chico!

Welcome to you and Chico. It seems he has already trained you quite well in the short time you've had him. Aaron's given you some very good advice regarding his aggression to other humans. It might take Chico awhile to get out of that pattern of behaviour, but keep persisting.

I bet someone nearby in your neighborhood lost him or worse they set him free. Sounds like a prior pet to me. My neighbors know Beamer and know where he lives in case he gets lost. I let him outside to fly & play but always with me outside with him. One night, while feeding my outdoor cats, Beamer while on my shoulder, got startled & flew into the night. I could not find him in the dark & I was so depressed. However, he had been waiting nearby all night & flew to us the next morning. The bird knows to follow us when we go to come back in the house. He flies back into the home. These birds are highly intelligent (know their food source) but I really believe they adopt us humans & feel like they are part of the family.