Acrobatic crows...revisited

Well, Tom Sienstra didn't write back. Instead, he used part of my email in his column last Sunday. Here's the excerpt (scroll down to the bottom to see):

-- "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?