One of the great things about birding is its capacity for surprise. No matter how much you may think a bird might be a given species, it is always worth a closer look because it could be something else. Yesterday as I was walking through my local patch, I saw large numbers of the usual waterfowl like Canada Geese and Mallards. Across the river were some small, very white ducks. At first, I though they were probably Common Mergansers since those are usually present along this stretch of the river from December through March and even April. However, I checked more closely, and they turned out to be Common Goldeneye, a less common species for the site. It was hardly a rarity, but it was still a present surprise and a reminder of the importance of testing assumptions.