I just finished reading the book 'Gifts of the Crow' by Marzluff & Angell, which is a popularization of current research into Corvid intelligence, consisting of anecdotes, experiments, and neuroscience.

Academics do, in fact, study recreation & play, language & song, and expressions of emotion like grief. They are considered indicators of some kind of intelligence worth studying. The book even devotes a chapter to each of those topics!