Suggestions/Tricks/Tips UM Cockatoo

I am a new mama to a 2 year old UM Cockatoo. He is thus far a handful, which we expected! He was a surrender to a resuce and while he does not seem neglected or abused, (thank-God) we are contending with old habits etc. He is loving, sweet, affectionate and we adore him. OF COURSE he is a screamer when he does not get his way. We are dilligent in ignoring him, no attention at all. If we can, we silence the room and leave. If he persists for a long time, and we must be moving about, we go to his cage, say nothing and cover the front so he cannot see us. For the most part it seems to do the trick.
He does it b/c he is having a tantrum we have learned, b/c if he wants on my shoulder, or something I have that I tell him "no" to while he is with me, he screams at me and puffs up. So, when we leave the room, or don't give him direct attention he starts to scream, totally tantrum.
Does what we are doing sound okay with you experts? Any advice on how long it should, (SHOULD) take to alter that behavoir meaning, til he "gets" it that it won't get him what he wants?

Next! We have him on open cage while we are home, and when he does need to be on his cage, he feels he needs to be with us! So, he just climbs down, and walks over. Which is a) not always convienent and b) not safe to have him underfoot, ON FOOT, lol, when we are doing chores etc. SO...We have ignored him when he starts to climb down with the idea that if that gets us to him every time, it will not be condusive to stopping it.

We ignore him until he is to us and then say nothing and put him back. He is VERY persistant, and we are now doing nothing but walking back and forth to the cage! I am thinking this isn't going to work either. I thought if it wasn't going to give him the desired result, eg: staying with us, then he would tire of it. What say you experts? What should I try? We have had him two weeks, and I have no idea what time frame is realistic for altering or changing a behavoir. How long should we persist with the same attempts at altering b/f we conclude it is not working?

THANKS SO MUCH in advance!!! Greatly apreciated!

Welcome to the forum and congratulation on taking on this responsibility.Is this your first parrot or large parrot?To tell you the truth 2 weeks is nothing to a 2 year old U2 aka Umbrella Cockatoo or any parrot.It all takes time for them to adjust and get used to you and their new surroundings.As for how long it should take to alter his screaming behavior or whatever other behavior he may be doing.BTW he may not show you all his little quirky things until he has been with you a little while longer(speaking from example).So far the ignoring the bad behavior is the right thing to do this means while he is screaming and throwing his tantrum ignore him don't even talk to him.Yes I share a home with quite a few including a 10+year old U2 that joined us 1 week ago I can't say I'm going through what you are going through but it's kind of a mini hell version of it.Henry insists on screaming like a pig and you have to realise there are others living in our home
too.Only my husband and the 6 small dogs as well as a total of 29 parrots including Henry.But every day he does his pig scream and wakes the whole house up.I'm sure if they could all have they're way Henry would be bound and gaged like a pig.But we are working with Henry because we are aware of his not so happy past.With patience and time things can turn around not just for Henry but for your guy too.They all have to have boundries too.Time out of cage as well as plenty of toys.He's still young have you tried foraging toys etc so he can forage for his food he may have too much energy and need to burn it off.One thing I haven't heard from Henry yet is the Cockatoo scream and I am hoping he forgot how.This is not my first Cockatoo.I have had several in the past including a Moluccan Cockatoo and when she screamed I swear the paint came of the walls.But all the Cockatoos had to go 8 years ago due to my asthma.I have Henry as a favor as a foster and I'm hoping I will not be affected by him while his home is getting prepared.

Marcia