Duck

=Canvasback Duck (Modern Animal)= By Cheryl Young 10C

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//The duck sees ALL who dares to oppose...//just kidding

The Canvasback (//Aythya valisineria)// is a large diving duck living in North America. The name itself is based on the canvas-like colour of its back. The following report explains the general habitat the canvasback lives in, and the adaptations it has undertaken until the present day.

**Scientific Classification** The Canvasback belongs to the Animalia Kingdom, the Chordata Phylum, the Aves class, the Anseriformes Order, the Anatidae family, the Genus Ayrhya and the A. valisineria species.

From Figure no. 1, the Canvasback duck has a variety of physical components that enables it to adapt to the present. Its white-coloured, gray and black tipped wings with a wingspan of 79-89 centimeters is also an important feature, enabling the Canvasback to reach speeds of up to 90 kilometers an hour flying, useful for fleeing predators and flying long distances. Its large breast shows the size of its lungs, as the Canvasback is a diving duck, and is able to spend a short period of time underwater to prey on aquatic plants and animals. Its large, webbed feet provide force to propel itself in the water when diving. The bill is also an important aspect, being able to dig up tubers and keep a good grip on one of its diet: insects. Because of those factors, the Canvasback is able to take food in a variety of ways, including: diving, tearing plants with their feet/bills, and grabbing prey from the water surface or the air. When diving, they use their cone-shaped heads to probe and extract submerged plants, another useful physical feature.

HABITAT
Since the canvasback's diet mainly composes of tubers, leaves, buds, seeds, roots, insect larvae and snails through diving and sometimes dabbling, the Chesapeake Bay is an ideal location for feeding. Its shallow bays provide a good geographical location for plants to grow. Although there was a decline in submerged aquatic vegetation growth, the canvasback adapted by changing their diet to commonly found [|Baltic Clams], which are found in Chesapeake Bay, having changed the duck's original diet of mainly plants to clams.

The Chesapeake Bay used to have a large amount of Canvasbacks winter there, but with the previous loss of aquatic vegetation which makes up a portion of the Canvasback's diet, the Canvasback's wintering range has shifted south towards LMAV, its waters abundant with submerged aquatic vegetation and invertebrates, (insects) creating an ideal wintering habitat for the ducks.



The Canvasback is a highly migratory bird. In order to maintain their diets, the bird has to migrate through the Mississippi Flyway to its wintering grounds: the mid-Atlantic United States and the Lower Mississippi Alluvial Valley (LMAV). Or, from the Pacific Flyway to the area along the coast of California. Its migratory path also provides a location for breeding in the North America prairie potholes. Refer to Figure no. 2.

During spring, fall, and winter migration, Canvasbacks are usually found in aquatic areas with available high densities of food, including large freshwater lakes, coastal bays and harbours, and large river deltas. During migration, the Canvasback may also take shelter in flooded fields, farm ponds and wetlands.

Taking a new mate each year, the Canvasback builds a bulky nest from vegetation within a marsh and lines it with down feathers, preferring to nest over water on permanent marshes surrounded by emergent vegetation, to provide protective cover from predators. They usually breed in areas with small pools, slow moving rivers and dense vegetation such as cattails, bulrush, reeds and river grass.

The Canvasback also breeds in Saskatchewan subarctic river deltas and near the middle of Alaska.

ADAPTATIONS
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Structural Adaptation 1
Being a diving duck, the Canvasback has adapted large webbed feet for diving. With large webbed feet, the Canvasback is able to propel itself faster and stronger through water, especially when diving. Being efficient and powerful swimmers, the Canvas duck's legs are strategically positioned near the rear of their body. They can spend up to 20 percent of their day swimming and dive to over 9 meters deep for 10 to 20 seconds with effective support from kicking their webbed feet against the water to propel themselves. Their hollow bones also play an important factor, as it enables the Canvasback to slowly drift back to the surface after diving.

A possible reason for this adaptation is related to its environment during its years of evolution. It may be that because the Canvasback spends a large amount of time in shallow water, its feet managed to develop a layer of skin between claws to enable it to swim through water, giving it an advantage over searching for food, which is mainly underwater.

Structural Adaptation 2
Another one of the Canvasback's distinguishing features is its blackish flat beak known as a bill. The structure of the bill is broad, containing serrated lamellae, which enable the bill to filter water through the sides of the bill. So, like many other ducks, the Canvasback's bill is wide enough to filter food from water, effectively draining the inside of its mouth so as to not swallow water and devour its meal.

This structural adaptation may have deprived from the environment the Canvasback feeds in. Having its diet composed mainly of submerged aquatic vegetation, the Canvasback frequently strips away plants from the bottom of bays to eat, trapping a large amount of water in its bill in the process. Because of this process, its bill evolved to the point that it is able to dispel water out and keep its food in.

Behavioural Adaptation 1
When migrating, the Canvasbacks form loose V-shaped flocks. The real reason behind this is that it boosts the efficiency and range of the Canvasback, particularly over the long distance it travels. All ducks except the one in front form tubes of circulating air of the bird ahead. This factor assists each Canvasback in supporting its own weight in flight. In a formation with 25 ducks, each duck can achieve a reduction of drag and increase their range at the same time. When flying, the Canvasbacks alternate positions as to spread flight fatigue equally among flock members. This also allows communication easier and allows them to maintain visual contact with each other.

The Canvasback may have adapted this formation due to its migratory path. Flying long distances between home ranges is physically demanding. On its own, a Canvasback creates a lot of drag, as air is pushed against by the wings while supporting the duck's weight at the same time. In a group, less drag is created and the Canvasback is able to use less energy and conserve it for the rest of its flight.

Behavioural Adaptation 2
One of the most important aspects of the Canvasback's behavioural adaptations is its nesting sites. Protecting its eggs from predators, [|Redheads] (who parasitize other birds' nests with their own eggs) and other Canvasbacks. The Canvasback will strategically build their nests within emergent vegetation above water, occasionally building them on land in protected areas surrounded by vegetation.

Due to the threats that pose towards the Canvasback, the duck has adapted by shifting its nesting grounds to safer, more secluded spaces to hide.

Physiological Adaptation
A hidden feature within the Canvasback is its hollow bones. The air trapped in the bones provide good flotation and enable the Canvasback to sit on water and preen its feathers. It probably developed this adaptation due to the amount of predators on land that are liable to kill them. And the only other safe place for the Canvasback to thrive was on the water, where the land mammals like [|raccoons], can't reach.