Forget pelvic bones and other biological structures. THIS is what can convince even the biggest skeptic that birds and dinosaurs share a common ancestry.
The way it's being held makes it look like one of those fake "bloody hand" illusions you can buy where it looks like you're wearing a glove and holding a severed hand, but your hand is the "severed" one. If anyone didn't think this was a puppet at first glance I'd be surprised.