There were two male Hooded Merganser at the refuge cruising around on a patch of water amid the ice, looking for food. They swam, dove, and came up for air. These small ducks are specific to North America, with the males very noticeable because of their black and white hood.
In the water, Hooded Mergansers hunt for food by sight. They have an extra eyelid, a nictitating (blinking) membrane, that they can deploy to protect their eyes, somewhat like humans who use goggles when swimming underwater. You can see it in the following shot.
They can also adjust the refractive property of their eyes to improve their vision under water.