On Nov 23, I went to Sacramento National Wildlife Refuge which is known for the waterfowl that come there for the winter.? There are hundreds of thousands of Snow Geese and no words can describe the scene they create.? There are two videos at the following link - one is 15 sec long but taken with a telephoto lens, the second is about a minute long taken with an iPhone.? We witnessed this scene for much longer, perhaps 15 minutes, but even the 1 minute video gives you a good idea.