Ottawa River, Ottawa, Ontario, Canada
A small fish-eating duck of wooded ponds, the Hooded Merganser nests in holes in trees. It is frequently seen on shallow waters where its only waterfowl companion is the Wood Duck.
The Hooded Merganser is the second-smallest of the six living species of mergansers (only the Smew of Eurasia is smaller) and is the only one restricted to North America.
Although up to 44 Hooded Merganser eggs have been found in one nest, one female probably does not lay more than about 13. Larger clutches result when more than one female lays eggs in a nest.
The Hooded Merganser finds its prey underwater by sight. The merganser can actually change the refractive properties of its eyes to enhance its underwater vision. In addition, the nictitating membrane (third eyelid) is very transparent and probably acts to protect the eye during swimming, just like a pair of goggles.