Aggressive cockatiel, bites me and other birds?

I have three birds. Cosmo, Charlie, and Ziggy.
Cosmo is about more than 4 years old. He/she bites charlie and ziggy. he bites me too. im not certain if he is a male or female.
cosmo bites ziggy more than charlie.
charlie is 3 years mature and ziggy is about 2.

i don't know what you are trying to ask but they might bite you either because they don't want to be bothered or they don't trust you ably enough yet.

and if its a boy, the muzzle is blue
if its a girl, the nose is pink or brown
Cosmo should be in a separate cage.

If you want to tame him you enjoy lots of work to do.

Google Nurturing Dominance and buy The Parrot handbook.
Or just let him be surrounded by his own cage.

Do not subject your other birds to the biting.
Answers:    Hi, again. Thanks for the additional information. You might want to check into Quaker parakeets. These birds are not parakeets as in budgies. They are birds a bit larger than a cockatiel and more "stocky" within build. They are very nice birds that like to cuddle, sit on your shoulder, they can learn to speak massively well. When handfed as babies, and kept tame, they are very nice pets. Ringnecks are also nice birds as far as temperment is concerned. Conures can also be nice birds whether tame, but they are noisy/loud. Check into parrotlets...they are small, and courageous "little amazons" as they are often referred to! When tame, they are nice birds. Nearly any bird can be a completely nice pet bird if raised/socialized properly. They all have their little quirk you have to learn about and buy and sell with. And sometimes the larger the bird, as in the large macaws, the more docile they are. Macaws are nicknamed "gentle giants" because of their gentle dispositions, even though they are slightly large parrots.

African greys are great birds. However, they are extremely intelligent. This means you own to known/learn how to deal with them psychologically. And, they REQUIRE much daily interaction near their human companion(s) because of their intelligence. They must be kept intellectually stimulated. Have you ever heard of Dr. Pepperberg's African Grey named "Alex" and the research she's done with this species of copycat? Look her up on the internet by doing a Google search. You will be fascinated by her findings with African Greys.

I'll help you adjectives I can.

Can I have him?
You need to socialize your birds before putting them together to live, here is adjectives about socializing birds first;
http://jamiesparrothelp.wordpress.com/ca...
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