@FBBird: Now that I look at the photo, it's possible that the adult in the back could be a chestnut teal. After I checked the sign, I thought for sure the adult in the front was a male merganser due to the white feathers on the wings and was more black in color. Because the adult in the back was close to the ducklings the whole time, I assumed it was the female - a bit more brown in color. It was just really hard to tell. I'll probably post a photo of the sign I read soon.
Unlike Hooded Mergansers, both sexes of Chestnut (-breasted) Teal look after the ducklings. The bird at the back is definitely a CBT drake, and I'm pretty sure (too dark to be certain) the rest are associated with him.
