Birds under Water 3 - Intrepid Divers

A series on birds at Halibut Point with diverse adaptations

to finding food below the water surface:

Dabblers, Plungers, Divers, and Pursuers.

Buffleheads, male and female

During the winter season at Halibut Point we enjoy the presence of ducks with the ability to forage for plants and small invertebrate animals on the ocean bottom. They may dive to depths of up to fifty feet. The birds that operate close to shore often find themselves in a zone of extreme turbulence, which adds to the wonder of their success.

The text for this article comes from the sportsmen's organization Ducks Unlimited. *

Bufflehead, diving

The body of a diving duck is much more compact and fusiform (wider in the middle and tapering toward the end) than that of a dabbler. Divers' wings are also more compact, which allows them to be compressed tightly against the body for greater diving efficiency. In addition, divers' legs are set much farther back on their body, and their feet are much larger and have a lobed hind toe. These adaptations help propel the birds while they are underwater.

Bufflehead diving and Harlequin observing

Harlequin Ducks

Harlequin male, diving and female, snorkeling

Diving ducks typically have higher body densities than other waterfowl. Just before they dive, the birds compress their feathers against their body, squeezing out air, which further reduces buoyancy. Next, with a single thrust of their powerful legs and feet, diving ducks arch their bodies upward and dive headlong.

Goldeneye, male and female

Goldeneye diving

Once underwater, the birds use their feet and wings to propel them downward in search of food. They steer during descent largely by shifting their head and tail positions. Once near the bottom, diving ducks use their feet to maintain a hovering position while the birds forage for aquatic insects, small mollusks, seeds, vegetation, roots, tubers, and other food.

Common Eiders

When the dive is complete, diving ducks simply relax their muscles, stop paddling, and ascend to the surface like a cork. Diving ducks that feed on submersed aquatic vegetation or sedentary invertebrates like clams return to the surface in almost the same place.

Common Eider

Harlequin Duck drakes

* The text in this article is taken from "Diving Ducks: Into the Deep," by John M. Coluccy and Heather Shaw, as published on the Ducks Unlimited website www.ducks.org.