My dad owns a male umbrella cockatoo who is 8 years old and my dad told me that at night sometimes he screams, which is normal for a bird at night that i have heard, and my dad will yell at Harry to go back to bed so that he doesnt wake the baby. But ever since my dad moved into the new apartment last year, Harry will sometimes talk to nothing. He will yell out HELLO and whisper and click his tongue. We have determined that the whole townhouse apartment building is very " active". The other bird a cockatiel doesnt do this. Do you think that maybe he is talking to a spirit?

Nope, perfectly normal night bird behaviour!

My Conure mumblings, clicks and grumbles to himself in his sleep all the time. When he hears a mysterious noise he'll wake up then grumble himself back to sleep.

The cockatiel is either a heavy sleeper or you just can't hear his noises. Cockatoo's are waaaaay louder than Cockatiel's in general so sleeping wouldn't change that.

It is possible that the new location and noises are waking the cockatoo up more often. As he gets used to the new night noises he may eventually quieten down again at night.

My bird Korkie doesnt make one peep at night. My dads cockatoo harry doesnt say hello or click his tongue anymore. Also we are going to have a "lockdown" in August. Thank you for responding!