Everything plays. Playing helps with motor and sensory skills as well as social behavior. It relieves stress. It teaches the young many important things needed for survival through the process of trial and error while they can still afford to make mistakes. It keeps relationships healthy. Social play helps children gain friends. Social play helps young lovers meet and flirt. Social play teaches us how to behave according to our social norms. It can give us solid practice on our role in society. Birds are no different than us. They play, although not all birds use social play. But young birds play more than fully grown birds. Bird play is often spontaneous and free-spirited. And corvids engage in all manners of play, including social play. It is easy to recognize a child playing. It can be just as easy to recognize a bird playing.
For example, when corvids play they often soar together on air currents, swoop down only to rise again over and over. It resembles a flying game of tag. Corvids also use ordinary objects as toys. They will often drop twigs, stones, leaves, or even their food midair and then catch them before they fall completely. Much like juggling or tossing a ball into the air. "One Hooded Crow repeated this performance dozens of times, catching his 'toy' after it had dropped about 36 feet (11 meters)".
He must have been one heck of a juggler. I can almost seem him as a human, throwing things up in the air and catching them in his mouth.
The following antics, corvid play was described in the Handbook of Bird Biology by the Cornell Lab of Ornithology:
Ravens have been observed taking turns sliding on their tails, feet first, down a snow bank as well as repeatedly sliding down smooth pieces of wood in their cages. Ravens have been seen playing with dogs, taking turns chasing it around a tree. One captive raven was observed tossing a rubber ball, pebbles, or snail shells into the air and catching them repeatedly. This same bird would often lay on its back and shift various playthings (toys) between its beak and its claws much like many children do with their toys. Other birds fell forward from a perch like an acrobat, in order to hang upside down by their feet, wings outstretched, then let go one foot at a time. While upside down, they would carry pieces of food, or shift items from beak to feet. One, while holding onto a branch with his feet, learned to propel himself around and around the perch by flapping his wings, like a gymnast on uneven parallel bars in a sort of 'loop-the-loop. The same captive ravens also played balancing games: carefully walking out as far as possible to the end of a tiny branch until it bent downward, turning them upside down; or trying to stand on a stick or bone held in the feet, while balancing it on top of and parallel to a perch made from a thick, wooden dowel.
When given time and the resources birds will play. The corvids do. Perhaps it is the corvids extensive use of playing, allowing themselves and their young to learn and develop through playing that allows them to thrive when other bird populations are declining at an alarming rate.
Podulka, Sandy, Ronald W. Rohrbaugh, Jr., and Rick Bonney, Editors. Handbook of Bird Biology. 2nd edition. Ithaca, NY: Cornell Lab of Ornithology, 2004.