If you're traveling in Ireland during the autumn and winter months, you might begin to see dark clouds rapidly form in the sky above you. If you look closer, you'll notice that these aren't clouds, but one of the most spectacular bird behaviors you've ever seen. Although it might be a rare and extraordinary sight to you, it's quite a common if you are from the United Kingdom or parts of Ireland. The best part about it is that they form almost like clockwork. It's fascinating, but it does appear with very precise timing every day. Spectators can schedule to see this marvelous sight and prepare their cameras just in time to catch it in action. However, the two girls in this video were taken completely by surprise.