whilst bumbling along the motorway somewhere near Nevers this August (end of) I saw a buzzard sized white-with-bits-of-black bird of prey in the air, and moments later saw another one sitting on a post next to the road. As we were travelling relatively fast (though not as fast as all the other traffic) it was difficult to get a good look. The closest I've been able to match it to is a Marsh Harrier, but I'm not convinced. Any ideas?