I found it very interesting that several birds at the zoo looked as though they were sitting like a human might or that they possibly had knees. And of course I can't remember a single name of these birds. grrrrr
But I did look into their strange sitting positions and found an answer on the san diego zoo blog. taken from that blog " the odd way his legs bend. Well, would it surprise you to know that birds’ joints bend in the same way as ours do!? So what looks like their knee is actually their “ankle” joint. Their knee is much higher on their leg, so high that you need to move aside their feathers near their stomach to see it."