There's an error on page 87. He states birds cannot move their eyes independently of their heads and this is completely wrong.
Although many birds like covids have less movement than parrots, which have full movement.
Quote <Eyes of most birds are large, not very round and capable of only limited movement in the orbits,[5] typically 10-20° (but in some passerines, >80°) horizontally. That's why head movements in birds play bigger role than eye movements.[6] Two eyes usually move independently,[6][7] and in some species they can move coordinatedly in opposite directions.> unquote
My parrot has full movement & will squint to pull a sill face.
The book is easy to hold interest, down to earth are the author's thoughts & sometimes humorous.
Corvids, like parrots, are not birds to enjoy being caged, even though they like their own cage the door must be open. So the author's bird has free run & this makes the story much more interesting. Only an uncaged bird will truly show their full personality.
Read the book it's delightfully written.