This is a study done on flamingos and not parrots but they have a VERY similar social structure (especially the flock oriented species) so I think that extrapolation can offer an accurate view of parrot societies. They are not as smart as parrots but this is not about their intelligence, it's about their social structure and needs and they are, like parrots, highly social, monogamous and mate for life. And, what they discovered is that they have rich and complex relationships that they maintain for years and years - and we are not talking about their mate, we are talking friendships. Furthermore (and this is, in my personal opinion, a super important discovery), they found that their interaction with each other is so essential to them that they even do it when they are ailing!
https://www.zmescience.com/science/flam ... s-5134246/