A bit off-topic: it's not just intelligence that's amazing about (some) birds. I highly recommend the book "The wonder of birds" by Jim Robbins. One of the ear

A bit off-topic: it's not just intelligence that's amazing about (some) birds. I highly recommend the book "The wonder of birds" by Jim Robbins. One of the earliest insights in the book is that birds are the dinosaurs that survived. They are amazingly adapted. The unusual thing is that each chapter is full of intriguing information and each one is a different topic. Like, how could birds possibly evolve wings? A wing is only useful if it's a working wing, and if a bird evolved half a wing it would be pointless, right? It turns out half a wing is useful. It speeds up running birds, especially up a slope. Feathers actually grow outside first, and the stem last. The amazing efficiency and optimization of their hearts and respiratory systems. Bird guano used to be so valuable that Incas punished bird killers with death. Natural fertilizers are very important if you try to make the most of poor mountainous soil.