So Tahoe makes this rather odd, but enduring sound and I wanted to know if he was just weird, lol, or if it was normal.

It happens when he is in a situation that is scary to him and I am assuming he makes the sound to make himself sound 'big and bad'... example I was 'flying' Rosie and we walked past his cage and he started making it... I assumed I had made him uncomfortable parading a flapping caique past his cage!

Anyhow, it sounds like chattering teeth.Reminds me of the sound a contented cockatoo makes- the beak chattering. Although this has a slightly different pitch- a bit higher. Anyone elses bird do this?

Normal sound. Gizzie makes that sound. They also make a sound like a ticking clock and a hiss.

i can't recall if winkie makes that sound. he does make a tiny squeal that sounds like a 3 yr old throwing a tantrum; he does it when he's mad.

Tommaso makes those same sounds. He does this when a plastic garbage bag is making crackling sounds. He also does the same thing when he is excited.
So he makes the same sounds and puffs up whether he is irritated or excited.