I think dogs are soooo smart. On the farm, our dogs, (Great Dane, shepherd mix, and a pit bull) were all able to tell the difference between a wild duck and a domestic one. They knew when the regular truck came to check the gas wells, and alerted when someone else came.
They told me when a tree fell down at the end of the field. They could smell bad weather coming. Once, Beau alerted me that there was a copperhead on the trail. They probably tried to tell me lots of stuff that I was too human to realize!