“…The irregular distribution of social play across taxonomic groupings suggests that the behavior may reflect an evolutionary response to particular ontogenetic and ecological circumstances. In the model proposed by Diamond & Bond (2003), birds would be predicted to engage in social play if (1) they belong to a relatively large-brained, altricial order, (2) they live in complex, stable social groups, and (3) they mature slowly and maintain an extended post-fledging association between juveniles and adults (Ortega & Bekoff, 1987;Skutch, 1987;Collar, 1997;Heinrich & Smolker, 1998;Power, 2000;Diamond & Bond, 2003).…”