Body shape/mass distribution in birds and their dinosaurian ancestors
nature.com
nature.com
https://www.smithsonianmag.com/science-nature/why-a-pterosau...
Flight is interesting because it’s so useful that it evolved at least 4 separate times. Pterosaurs, birds, insects, bats.
If you include gliding or falling with style in your definition of flight, then it evolved even more times. Sugar gliders and flying squirrels for example. Completely unrelated. Both have a similar solution to gliding. Some snakes can glide too!
I've had a couple for over a half a decade and they surprise me with their intelligence and their behaviors every day. Decided they might be the pet for me after studying birds in the wild for many years before that.
That said, they're also a handful and don't suggest anyone adopt or buy one on a whim. They tend to latch onto one person. In my case, they love my wife more than me, but we're still "bros". That means they stop caring about attention from me as soon as she walks into the room. It's a little annoying, but that's just the way they are with bonding to a mate for life.
Many parrot rescues will let you foster one for a while, just to get an idea if they're the kind of companion you would want long term