by Graham Peters
Well known to waterfowlers for their erratic yet agile flight and raucous whistling, American wigeon have many attributes that make them a pleasure to observe and hunt. These medium-size dabblers are widely distributed throughout North America, but are not especially abundant anywhere except in certain migration and wintering areas. According to U.S. Fish and Wildlife Service (USFWS) estimates, wigeon ranked eighth in abundance in 2010 behind mallards, blue-winged teal, scaup, shovelers, pintails, green-winged teal and gadwalls, respectively.
Many aspects of wigeon breeding biology remain poorly understood because the birds typically nest in remote areas at low densities. Along with pintails, they nest farther north than any other dabbling ducks. Their primary breeding range extends from western Alaska to Hudson Bay in the north to the Prairie Pothole Region (PPR) and U.S. Intermountain West in the south. In recent decades, wigeon have expanded their breeding range eastward into Ontario, Québec and Atlantic Canada.
Among dabbling ducks, wigeon are relatively late nesters, with peak nest initiation typically occurring from late May to early June. Females breed during their first year of life and will renest if their first nest is lost. They prefer to nest in tall, dense, shrubby vegetation. Even on the wide-open prairies, wigeon nests are often found near or under snowberry bushes.
Male wigeon typically depart nesting areas toward the end of the incubation period to undergo their summer molt on large lakes. Hens begin to molt six to seven weeks after hatching their broods. As a result, adult males typically begin the fall migration earlier than females and immature birds.
Wigeon are among the first waterfowl to migrate south each year, with some particularly early migrants departing in late August. Wigeon use every flyway during migration, but are most abundant in the Pacific Flyway. They gather in large numbers on fall staging areas for varying durations before finally settling on their wintering grounds. For example, when wigeon first arrive in the Pacific Northwest in September and October, the birds often congregate on bays and estuaries along the coast, where aquatic plants are a reliable food source. As tidal fluctuations increase and heavy rains fill interior floodplain wetlands later in the fall, many wigeon migrate inland. Here the birds find an abundance of food in seasonal wetlands and on adjacent uplands.
BIRDS OF THE BOREAL American wigeon are among several species of waterfowl that breed largely in North America's boreal forest. This immense region's countless glacial lakes, bogs, beaver ponds and other wetlands produce almost as many waterfowl as the prairies, earning the boreal forest the well-deserved nickname "the other Duck Factory." In addition to wigeon, this region raises the majority of North America's lesser scaup, green-winged teal, ring-necked ducks, and scoters, as well as significant proportions of this continent's mallards, pintails, and canvasbacks. Boreal wetlands also provide essential migration and molting habitat for ducks and geese that breed on the prairies and in the Arctic.
Ducks Unlimited has long recognized the boreal forest's importance to waterfowl and was among the first conservation organizations to work to conserve key wetland habitats in the region. In 1989, DU began mapping extensive wetland systems in central Alaska to assist efforts to conserve them. DU subsequently expanded its conservation work in the boreal forest of Canada, launching its Western Boreal Program in 1997. Through this initiative, DU works with a broad coalition of partners dedicated to conserving boreal wetlands and wildlife, including The Pew Charitable Trusts, U.S. Forest Service, U.S. Fish and Wildlife Service, Canadian Wildlife Service, and many other groups. In 2010, the Forest Products Association of Canada signed an agreement ensuring that more than 170 million acres of boreal forest will be managed according to high environmental standards, which will help protect many of the region's most important wetlands for waterfowl and other wildlife.
Unlike many other dabbling ducks that mainly consume seeds and grain during fall and winter, wigeon prefer to forage on the stems and leaves of aquatic and upland vegetation. In fact, large flocks of wigeon can often be observed in uplands grazing on grasses and forbs. Wigeon have a short, thick bill that is well designed for grazing. Their legs and feet are also positioned farther forward on their body than in many other ducks. This adaptation is good for walking—and even running—on dry land, but makes diving difficult. Perhaps this is why wigeon regularly congregate with rafts of feeding coots and diving ducks in deeper waters. They are even known to steal strands of vegetation from the bills of these diving birds, giving rise to the wigeon nicknames "robber duck" and "poacher duck."
Nearly half of the continental wigeon population can be found in the Pacific Flyway during winter. Major wintering areas in the West include Washington's Puget Sound, Oregon's Willamette Valley, and the Central Valley of California. Continentally significant numbers of wigeon also winter on the southern high plains of Texas and New Mexico, in the Mississippi Alluvial Valley, and along the Gulf and Atlantic coasts. Harvest statistics reflect their migration and wintering distribution. The largest wigeon harvest occurs in the Pacific Flyway, with an average annual harvest of 370,000 birds since 2000; followed by the Central (190,000), the Mississippi (150,000), and the Atlantic (30,000).
According to USFWS estimates, wigeon had a breeding population of 2.4 million birds in the traditional survey area in 2010, similar to the previous year's estimate and the 1955–2009 average. In recent decades, wigeon have increased in some portions of their breeding range and declined in others. Their breeding grounds can be divided into three major components: the Canadian PPR, Canada's western boreal forest, and Alaska. In 1971, 1.6 million wigeon were surveyed on the Canadian prairies.
WIGEON OF THE WORLD Three species of wigeon—American, Eurasian, and Chiloe—are among the world's 64-member Anatini tribe, collectively known as the dabbling ducks. Based on their morphology (physical characteristics) and behavior, wigeon are most closely related to gadwalls, falcated ducks, and Cape teal. Each of these wigeon species has a similar syrinx (the vocal organ in birds), downy plumage as ducklings, and adult plumage.
As its name suggests, the Eurasian wigeon is found across Europe and Asia. These colorful birds appear to be arriving on this continent's shores in increasing numbers, especially in the Pacific Flyway, offering waterfowlers an opportunity to bag one of these rare trophies. The Chiloe wigeon is found in southern South America.
By 2006 that number had fallen to 500,000 birds—a 70 percent decline. During the same period, pintail populations in the Canadian PPR declined by 60 percent. Wigeon numbers have also declined in Canada's western boreal forest, although not by as much as on the prairies. Fortunately, much of the wigeon decline in Canada has been offset by increases in Alaska. In 1955, fewer than 50,000 wigeon were counted in the state. Today that number approaches 1 million birds. Without this dramatic increase in Alaska, today's continental wigeon population would be less than half that of 1955.
It's unclear why wigeon populations have increased in Alaska and declined in areas of Canada. Possible factors include distributional shifts on their breeding grounds, loss of habitat in the Canadian PPR, and degradation of migration and wintering habitat. Research measuring wigeon reproductive success in different parts of their breeding range and survival rates on key migration and wintering areas could provide answers to these questions. In the meantime, Ducks Unlimited will continue its work to protect and restore wetlands that provide vital breeding, migration, and wintering habitat for wigeon and other waterfowl throughout their annual cycle.
Graham Peters is a DU biologist based in Vancouver, Washington.