Ahhh Miss Jojo, sounds like you got a female ringneck being protective of her cage

. Here are few things you can do to help minimize this behavior. I would start by removing her cereal box as any cavity is considered a nesting site. The female rignecks genetics are taking over and she is becoming more territorial. So, as hard as it might be--i would remove the box

.
As Bec said, i would also do a wing clip as this will make the female much more dependent on you and your family members for interaction. When her wings are clipped, they are forced to deal with you. Believe me, my most tamest ringnecks become monsters once their wings are grown

. They like to start to make decisions for themselves. Ha Ha Ha
Also, start a positive reinforcement program. Teach your bird recalling, waving, turning around, etc.. This little game will keep her more stimulated and will allow you to control her behaviors more effectively.
The final 2 important rules--never let your female come out unless you physically take her out--that means she steps up onto your finger inside the cage before she may exit.
Also, the last golden rule--if she becomes too territorial--move the cage around weekly--this can make a night and day difference. Move the toys around, perches, and bowls.
Hope this helps and as Bec said--please keep us updated!
Best Wishes

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IMRAN-C