Carrion Crow apparently having fun!

On my way to Cemlyn at the weekend my attention was drawn to a pair of Carrion Crows perching on telegraph wires. One bird was hanging perfectly upside down and at first I thought it was snagged. As I neared the crows it swung around to upright itself from its dangling position. I couldn't see any reason why it would be doing it but for the fun of it or showing off to its mate. I had seen Galahs do this in Australia but that was with wings outstretched in a rain shower to essentially wash their underwings. Also on my way to work today I noticed a Collared dove on wires stretching its wings in the rain to clean them, but this time the bird was upright!