To further reduce their buoyancy, divers compress their feathers against their bodies before diving, reducing the volume of air trapped in their downy feathers. The trade-off for divers, however, is clumsiness on land, which almost completely precludes them from foraging in upland habitats.ĭivers are also less buoyant than dabbling ducks, geese, and swans because their bodies are denser and more compact, which helps them stay underwater for prolonged time periods. Their legs, which are also stouter and feature a lobed hind toe, propel them through the water with greater power. In comparison, the feet of pochards (diving ducks), stifftails (ruddy ducks), and sea ducks are positioned farther back on the body, closer to the tail. The trade-off is that their swimming capabilities are somewhat reduced. The feet of these waterfowl are positioned well under the body to provide support and allow foraging on land. And finally, northern shovelers and similar species like the pink-eared duck of Australia are known as strainers because they slurp up water and jet it through lamellae to extract food items.ĭabbling ducks, geese, and swans are at home in both wetland and upland environments. A few species, like the lesser snow goose, are known as grubbers because they uproot grasses and sedges to eat roots and tubers. Grazing is another common feeding mode employed by species such as the Canada goose and American wigeon. Pochards, stifftails, and sea ducks are commonly referred to as divers because they seek out food below the water's surface. Ducks from the tribe Anatini are collectively known as dabbling ducks, but swans and geese will also tip up to feed. Perhaps the most common, recognizable feeding mode is tipping up or dabbling. For example, the extremely long neck of trumpeter swans allow them to access food resources up to 30 inches deep, while the much shorter neck of green-winged teal limits them to feeding in only a few inches of water.įINDING FOOD Waterfowl employ a variety of "feeding modes" to satisfy their daily energy needs. However, their varying neck lengths allow them to access foods at different water depths. Trumpeter swans, Canada geese, mallards, and green-winged teal all tip up or dabble (see "Finding Food") to forage on submersed aquatic plants. These adaptations allow different waterfowl species to intermingle in the same wetlands without competing for the same food resources. Over time, waterfowl have developed numerous adaptations to exploit these habitats and their abundant food resources. These diverse environments provide a veritable smorgasbord of food, including roots, tubers, submersed and emergent vegetation, seeds, and small animals. Waterfowl are an extremely diverse group of birds capable of exploiting a variety of aquatic (freshwater and marine) and terrestrial habitats. How can it be that all of these waterfowl species can coexist in the same wetland? Meanwhile, a pair of trumpeter swans tip up in the shallow water, and a group of lesser scaup dive and resurface farther from shore. A small pod of northern shovelers swims in unison, probing the water's surface with their spatula-shaped bills. JamesĪs dawn crawls over the marsh, seemingly every corner of the wetland springs to life with waterfowl activity.
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