Diving ducks prefer larger and deeper waters and will feed by diving to the bottom of the water. Their legs are located close to their tail and usually walk poorly on land. Most divers will patter along the surface of the water to take off. Their wing patches are normally dull colored.
Mergansers are diving fish ducks with spike like bills. Most species have crests and are slender ducks. They are generally poor eating ducks as their diet consists chiefly of small fish. The hooded Merganser nests in tree cavities. It is easily identified by the fan-shaped white crest that may be raised or lowered. The common merganser is similar to the hooded merganser but larger. The male has a whitish body, a black back with a green-black head.
Ringneck ducks are the most common wintering duck in Florida. They are found rafted up in great numbers on large bodies of water, such as Lake Okeechobee. This diving duck has light colored bands at both the tip and base of the bill. There is no discernable ring around the neck.
Source: FWC Hunter Education Program