Some years ago, I was running a wave bar in a glider at c. 12,000' in the middle of Wales, above 7-8/8 cloud and I met a small squadron of geese doing the same thing only in the opposite direction. They were right in the best bit of the lift and going for it, wings locked, staggered formation and beaks in raised mode. These guys knew all about TAS, wind components and energy conservation...
