This thread got me to thinking, "Hey, I have a couple of bird books, I'm going to go look at them." One of them is Rosemary Low's "Parrots, Their Care and Breeding". It was printed in 1980 and I don't think I've picked it up in twenty years, but it's still got a lot of good information in it. Incidentally, I met Ms. Low at the first international parrot convention in Tenerife back in the 80's. I had to take a second job delivering pizzas to afford the trip. They had a huge parrot park there. Alas, it's all a fading memory to this aging brain.
Back to the subject of books, I just checked out two books from the library this week. They weren't especially useful. The author of one of the books, a self-styled bird whisperer, writes about one 17 year old cockatoo she was evaluating because of new onset aggression. She wrote: Sitting in their kitchen that sunny morning, I asked the bird what was the problem. He looked me straight in the eye and said, "I'm gonna get married". His owners of 17 years nearly fell out of their chairs. They had assured me he had never been taught to say that. Yeah. I think a bit of literary license may be at work here.