I have encountered Zapdos five times, then I figured out it can be found by checking coastal Kalos Pokedex, but Zapdos is always on the move, and it always moves more randomly than Thunurus in Pokemon White... I once traveled all the way from Anistar to Route five to find it, it kept its position, then when I travel anywhere else without flying and without running/roller skating, it'll change its position more frequently and now I'm puzzled on how to catch it if it's always on the move like this...