Why is my cockatoo suddenly aggressive only to me at 2 years old?

What you can do really depends on what the cause is, so trying to find the cause is best. If you suspect illness, seeking out a vet appointment is a good first step to rule out any health issues or pain that can cause behavioral changes. Sometimes, aggression can be caused by boredom, stress or even an urge to mate. Adding in enriching toys or allowing Coco to explore his environment may help with boredom and keep him happier and occupied. Moving his cage to someplace quieter or without harassment by other pets and people can help reduce stress in addition to adding some fun toys or treats to play with. If he is trying to mate, sometimes changing the daylight hours and decrease protein amount in the diet can help, as well as distraction with interactive toys/ignoring/avoiding the behavior. If he does seem stressed and lash out, giving him a chance to calm down and relax before interacting again may also help.

If Tootoo was otherwise happy and calm around family, but recently began to bite there are a few possibilities. One can be pain or underlying illness, which may cause behavioral changes such as sudden aggression as a way to hide illness. A vet checkup to rule out any health issues is always best. Being startled or scared by something may also cause a bird to lash out or become more aggressive, such as if a new family member or pet was introduced, new items, or even loud or strange noises. Giving Tootoo some time to relax and settle down, and then gradually regaining trust with treats and toys may help decrease aggressive behavior. Birds that want to mate may become aggressive toward family they see as "competition" to a mate (or someone they consider a mate, such as a family member). Discouraging this behavior by stopping contact when he becomes aggressive, not giving attention to perceived mating behaviors, or using toys and treats to discourage and distract from bad behaviors may help.

Losing a mate or part of the flock can be traumatic. Try to gradually reacclimate him to you. Begin by simply sitting by his cage for ever increasing periods of time. Speak softly and move slowly around him. End each visit with a small treat. Once he is fine with that, place your hand in the cage for ever increasing periods of time. He may squawk and flap and move away at first. That's fine. Do not attempt to touch or pet him. Once he settles down, you can coax him closer to you using treats. It will take time and patience, but eventually you should be able to win him over and get him to per h on your finger.

This is a very common issue, especially with birds that are kept alone or are not otherwise stimulated/enriched in their environments. A good first step is to try and distract Mango with other enrichment, such as toys he can preen and play with, puzzle toys that have food or treats that he has to work to get, or even activity centers where he can climb around and explore/chew on toys. Having him lose when around other people is not a good idea, especially if he bites or becomes aggressive. You can, however, reserve a special favorite treat of his to use only when you have company. Have your friends and family that come by toss this favorite treat to Mango every time they come visit to help him start to associate them with positive things (yummy food) instead of negative (taking away his time with you!). If you have other family that lives with you, having them start to spend time with Mango (and you less) can also help him overcome his attempts at over-bonding/interest in you. Adjusting Mango's diet (less protein/fat) and daylight hours (less sunlight) can also sometimes help change hormone levels in birds that want to mate, and return them to a more consistent baseline behavior.

Thanks for reaching out and including photos. Training birds can be difficult, especially as they reach sexual maturity. Continue with the training process and establish a dominance hierarchy with you primary. A book titled "A Guide to a Well Behaved Parrot" is a good start. Good luck.

Thanks for reaching out about Keke. It appears as if he might be hormonal, searching for a nesting site, becoming territorial. Monitor for appetite. If becomes lethargic or eating less, a veterinary visit is recommended. Good luck.

I'm sorry to hear Minty isn't doing well. It is possible that there is an underlying issue such as pain or injury causing the aggression, especially if it came on rapidly or is a complete reversal of their usual behavior. Other issues such as sexual maturity, being startled by something, etc may also cause a bird to become fearful or aggressive. Removing any nesting material, providing some fun toys to interact with and spending time bonding/offering treats when Minty is calm and relaxed, rather than nervous or aggressive may help. If the behavior continues or worsens, or you see signs of illness, seeking a vet exam is always best to rule out any potential issues that could be causing the change.