Conure Behavior (hormones? or jealousy?)

[Vhenry20]

So for reference I have one green cheek conure and I had three budgies before I got him(i call him a he i dont actually know yet whether he is male or female) yesterday i got another budgie (a male, my previous 3 were female) and he(my green cheek) has displayed some different behavior since then. When they are all out together he will approach very close to the male budgie and sort of act like hes gonna preen him but like it doesnt look like he is actually preening him and it looks different than how he acts with the other budgies. and he has hit his beak on the ground a few times near him which i have never seen him do before yesterday and ive had him for like severrrrall months now. Then today while on my shoulder my 5 year old son came up to me and he jumped off my shoulder and bit him on the nose, it didnt break the skin but did leave a mark. He has NEVER done that before. he does occasionally nip at the kids fingers when they cross his boundary lines but as i explain to them it isnt usually aggressive just like a warning bite to let them know he isnt ok with what they are doing and its his defense mechanism but this was like, an attack. he is usually the sweetest little bird and im unsure at this point if this has to do with it being the time of year and him just being a hormonal little birb or if it has to do with jealousy surrounding the new addition. he has never showed aggression to the other budgies before. Again, just for clarity i dont know that he is a male we call him a he because it just feels right lol. Any thoughts and opinions are appreciated. as of right now he is seperated from the kids and other birds. i do not like to use the cage as punishment but i also cant have him out attacking my kids when i dont know what is going on. thanks