Loons or Ducks? Can Someone Help Identify the Birds Seen on Lake Superior?

Yesterday while driving home from work, I noticed what I thought was a group of maybe 10-12 loons swimming off Barker's Island in Superior, which I thought was a rare sight, but now I don't think they were loons, but rather ducks.

When I first noticed the group of birds, I pulled into the parking lot near the Richard I. Bong Veterans Historical Center and took some photos with my iPhone, but the birds were too far offshore to get clear photos, so I went home to get my good camera with a telephoto lens to see what I could capture.

When I returned, the waterfowl were still hanging out and I started to zoom in and take some photos, and after walking around and taking photos for maybe 30 minutes I began to think what I was looking at weren't loons, but some sort of duck.

The birds looked a lot like loons and they were diving like loons do, but something about the colors and shape/size didn't seem very "loon-like." Some other birds were hanging out and flying around that were very clearly ducks, so in the end I left with my photos and decided I needed to get the photos on a bigger screen and see if I could determine what they were.

After examining the photos on a larger screen and sharing the photos with some coworkers, friends, and family, I was still confused about what type of bird these were as the results from my survey of those people was a 50/50 split between loons and ducks.

But, after consulting with my uncle, who works with wildlife and is VERY knowledgeable about these types of things, I think what I was looking at were Goldeneye Ducks, and after looking up photos and videos of Goldeneyes, I was convinced that this is the bird I was looking at.

Goldeneyes do dive to look for food, just like the loon does, and the coloring from a distance mixed with the conditions of the lake and light at the time gave the appearance of a loon, but now I'm confident that what I was seeing was Goldeneyes.