-- "As we sat there, looking up, one pair of crows would fly in tandem and occasionally, the larger crow, would roll 180 degrees upside down and cruise directly beneath the smaller crow. This upside-down behavior occurred roughly every 10-15 seconds and lasted for about 10 minutes. Was this a mating ritual? Training for attacks? Play? We weren't sure." -- Sean Ness
Note: Just like some of the things dogs do, they do it because they can.
Was hoping for more...but I got my 15 seconds of fame, huh?