Hobbies And Interests
Surface Paddlers
When people think of birds that swim, they often visualize ducks paddling around a pond. True, these are aquatic birds, but they do not usually swim underwater for any length of time or distance. They float on the surface of water, their feet paddling quietly beneath them to propel them forward. In search of food, they will tip their tail feathers up and willingly dunk their heads and necks underwater, but their bodies won't move very far from the surface, if at all. Some other paddling birds include geese, swans and coots. Of note, the coot has lobed feet enabling it to "run" across the surface of water to take off.
Flightless Swimmer
Another obvious, but more accurate, example of an underwater swimming bird is the penguin. This bird has become such a proficient underwater swimmer that its front appendages no longer function as wings but as water paddles. A flightless bird that waddles on land, it effortlessly "flies" underwater, with its solid bones -- compared to the hollow bones of flying birds -- lending it weight so it can stay submerged for several minutes at a time.
Sky Divers
Some birds spot their prey from the sky and dive straight into the water, using the momentum from the sky dive to carry them beneath the surface. Some of these submerge only about a body length below the surface before emerging again, often carrying fish with them. Others plunge farther beneath the water, sometimes even chasing after their prey with paddling feet and streamlined bodies. They spear the fish with pointy beaks or scoop them up and store them in roomy bills until they regain the surface to eat their food above water. Some examples of these kinds of birds include gulls, pelicans, gannets and terns.
Surface Divers
Some birds begin their underwater dive from the water's surface instead of the sky, with most of them paddling along in the water, then simply ducking their heads and sliding under the surface. Smaller ones leap into the air slightly before diving under the water. Once beneath the surface, some birds fold their wings in close to their bodies and continue propelling themselves deeper by using their webbed feet as flippers. Others also use their wings to paddle. Some examples of surface diving birds include loons, grebes, auks, coots, petrels, anhingas and cormorants.
A Professional Fisher
Although a clumsy flier, the cormorant is such a skilled surface diving swimmer and predator that Asian fishermen train these birds to fish for them. The hungry cormorant has been known to deplete a pond's entire fish population and even faces predation control in some cases. Like the anhinga, the cormorant lacks the waterproof feathers enjoyed by other diving birds. This aids underwater swimming but requires the bird to spend considerable time with its wings spread to dry out feathers. Wet feathers do not fly well.