“Hooded” is something of an understatement for this extravagantly crested little duck. Adult males are a sight to behold, with sharp black-and-white patterns set off by chestnut flanks. Females get their own distinctive elegance from their cinnamon crest. Hooded Mergansers are fairly common on small ponds and rivers, where they dive for fish, crayfish, and other food, seizing it in their thin, serrated bills. They nest in tree cavities; the ducklings depart with a bold leap to the forest floor when only one day old.
Hooded Mergansers find their prey underwater by sight. They can actually change the refractive properties of their eyes to improve their underwater vision. In addition, they have an extra eyelid, called a “nictitating membrane,” which is transparent and helps protect the eye during swimming, like a pair of goggles.
Information from the All About Birds website, , © Cornell Lab of Ornithology.