I just thought id post as i thought it was interesting, i was recently parrot sitting my moms macaw as she was away and i got worried that when i went out she might squark continuously by being in a new place etc and i live in a bottom floor flat so neighbours would be little upset hehe. I put my laptop on record so it recorded all the noise when i went out... two hours later i came home and listened to it and not a peep from my macaw,cockatiels or patagonian conure!! or my two dogs... i was amazed but nice to know when i get home they make what i think are happy noises when they see me 
bit sad of me i know but i thought it was interesting 
xx