Nature Watch: Dabbling in Winter Waterfowl
About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.
Overview
A casual glance at a shallow lake may reveal exotic-looking plants growing out of the water. They aren’t plants, but the tail-ends of waterfowl. These ducks are known as dabblers, the name originating from the habit of tipping forward in the water to access food.
There are seven species of wintering dabblers on our islands. Another two – Cinnamon Teal and Blue-winged Teal – are only present for the breeding season.
Also known as puddle ducks, thousands of dabblers migrate out of Alaska and Canada, choosing to leave as their breeding grounds fill with ice and snow. They range in size from the 14-inch Green-winged Teal to Mallards that can reach 28 inches in length.
These waterfowl have a variety of feeding styles. Northern Shovelers rake their broad, ridge-lined bills through the water, filtering out tiny plants and invertebrates. American and Eurasian Wigeons dabble for vegetation and will come ashore to forage on short grasses. They also specialize in hanging out on deeper water, waiting for coots or diving ducks to surface with food that can be quickly snatched away.
Mallards eat just about anything and are often seen in agricultural fields picking up grain left after harvest. Cryptically colored Gadwalls forage mainly on stems and leaves of aquatic plants taken on the surface or by dabbling.
Green-winged Teal may be thought of as “honorary” shorebirds, sharing the same habitats with sandpipers and plovers. They filter mud through their bills, retaining seeds and invertebrates. As with all dabblers, they spend up to two thirds of the night in feeding activity. This allows them to forage without having to keep an eye out for aerial predators.
All these ducks have several adaptations that facilitate the dabbling lifestyle. Legs are set forward on the body, making it easy to walk on land. Large wings relative to body weight allow them to fly slowly and drop down with pinpoint accuracy. They also can rocket straight up from land or water, something diving ducks cannot do. Lastly, they have a hardened hook or tooth on the end of the bill, used for stripping covers from seeds.
Diving ducks are specialized for swimming underwater. Dabblers can dive but usually for short durations and mostly to escape predators. I once witnessed a Mallard dive underwater in a pond to escape an attacking Northern Goshawk.
Dabblers are some of the most numerous bird species present in winter. You can find these fascinating ducks in many locations on and around our islands. They grace our fields, coastlines and wetlands until the pull of spring sends them north once again.
Fauna: Northern Pintail (Anas acuta)
Elegant is the best word to describe Northern Pintails. These long-necked ducks are a common sight in our region.
The name pintail originates from the elongated central tailfeathers that comprise about one quarter of the male’s (drake’s) length of 25 inches. Drakes have brown heads and a dark nape. The breast and neck are white, while the body is grayish. Hens are mottled brown. Both genders have grayish-blue bills.
While a few pintails are found here year-round, the vast majority are migrants from Alaska and Canada. They migrate mainly at night, flying at speeds of nearly 50 miles per hour.
Pintails often feed by upending in the water. Their long necks allow them to reach invertebrates and plant material inaccessible to other dabbler species. They also feed by swimming with their head submerged. Seeds of bulrush, other sedges, and pondweeds are favorite foods. They also waddle through fields, looking for grain left after harvesting.
As with most waterfowl species, the most dangerous part of life is during the vulnerable egg-to-chick stages. Adults are preyed on by Bald Eagles on the wintering grounds.
Pintails begin to form pairs in late winter, continuing the process during migration. Early spring brings a mass exodus of pintails. They breed farther north than any other dabbler, so an early exit is a must.
Search for these classy ducks in lakes, sheltered saltwater areas, and agricultural fields.
Flora: Bulrush (Scirpus species)
Bulrush is a name for several plant species in the Sedge family. They are grass-like flora found in and around wetlands.
Sedges in general have stems that are triangular in cross-section, which separates them from reeds. Every beginning botanist learns, “Sedges have edges, but reeds are round.” Sedge stems tend to be solid, while those of reeds are hollow.
Bulrush stems grow from rhizomes and produce flat, grass-like leaves. Flowers are held in clusters, usually in the shape of a spike. The blooms are not showy, being brown or greenish brown, although a few may be whitish.
Reproduction of these hardy plants can be through seeds, or by shoots extending from the rhizome. The seeds are broadcast via wind or water currents.
Bulrush species play a significant role in wetlands. They stabilize soils and are just about the only flora that can compete with cattails. The latter, while important for many animals from invertebrates to birds, often form dense monoculture stands that limit biodiversity. Bulrush can break up the cattail monopoly.