Even used Thesaurus.com to try and find a better word than herding but I could not because that is what these duck are doing to the herring. It is a little hard to see in this photo but the dark shapes with white patches are common murres under water feeding on a school of herring. The herrings defense is to form a ball that revolves within itself. We are next to this herring ball on a whale watching tour because there are NO humpback whales close. If they were close we would be back from the herring ball because they like to lunge feed and you do not want to be to close if that is happening. Check May 9th post.