- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding resident and migrant that is restricted primarily to west-central and northwestern Minnesota; seen every winter in the southern half of the state at a few sites where there is open water. The Gadwall was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).
Broadly distributed throughout the western United States, including the northern Great Plains, and the Canadian Prairie Provinces; scattered populations can be found also in Alaska, northwestern Canada, and throughout portions of the Great Lakes region. The core of the species’ breeding population occurs in the prairie potholes of Canada and the United States (Figure 1).
A game species, the Gadwall is assigned a Moderate Continental Priority by the North American Waterfowl Management Plan, and a Continental Concern Score of 8/20 by Partners in Flight.
A medium-distance migrant that winters in the southern United States and Mexico. Populations in the western United States are year-round residents.
A dabbling duck that feeds primarily on submerged aquatic plants.
There was a time, Roberts (1932) wrote, when ducks were abundant, when the “Gadwall, or Gray Duck as it is known among hunters, was one of the commonest species in the prairie.” During a visit to Grant County in 1879, Roberts and his colleague Franklin Benner described it as “the common Duck in Grant County,” as common, if not more so, than the ubiquitous Mallard. Other friends wrote him regarding the species’ abundance in Otter Tail County in 1881, and at Heron Lake in Jackson County and Mud Lake in Marshall County in 1901. Yet, in the early 1900s, Roberts noted that the species experienced a significant decline as the state’s western prairies were settled:
It was one of the Ducks that suffered most severely from the settling of the country, probably as much from the breaking-up of the prairie, where it commonly nested, as from the hunters.
Then slowly, beginning in the 1920s, numbers began to rebound in response to the enactment of harvest regulations and passage of the Migratory Bird Treaty Act in 1918. By 1932 Roberts considered the Gadwall to be a breeding resident throughout “much of the prairie and open woodland regions of the state.” Confirmed nesting records (nests with eggs), however, were available only from Jackson and Grant Counties. Several broods of small young were also observed in Marshall County.
In 1975, Green and Janssen reaffirmed the Gadwall’s breeding distribution as spanning the western and southern prairie regions, noting that it was most abundant at the Agassiz National Wildlife Refuge in Marshall County. A few years later, Janssen (1987) cited scattered breeding records farther east, specifically in Aitkin, Crow Wing, and Mille Lacs Counties (his map identifies Mille Lacs County, but his written account mentions Cass County). His map delineated a total of 11 counties where nesting had been confirmed since 1970: Aitkin, Big Stone, Crow Wing, Lac qui Parle, Le Sueur, Lyon, Marshall, Mille Lacs, Pennington, Pope, and Yellow Medicine. When Hertzel and Janssen (1998) provided an updated map of counties with confirmed nesting since 1970, they deleted the Aitkin County record and added Lake of the Woods.
The Minnesota Biological Survey (MBS) reported 91 breeding season locations. All but 2 of the records were in the western and south-central regions of the state. One report was from as far east as central St. Louis County, and the second, from Carlton County (Minnesota Department of Natural Resources 2016).
During the MNBBA, participants reported 280 Gadwall records in 4.2% (201/4,737) of the surveyed atlas blocks and in 3.9% (92/2,337) of the priority blocks; breeding was confirmed in 28 (0.6%) surveyed blocks (Figures 2 and 3; Table 1). The birds were reported from 41 of Minnesota’s 87 Counties and were confirmed breeding in 8 counties. Five of the counties where breeding was confirmed were new to the list published by Hertzel and Janssen (1998): Grant, Lincoln, Polk, Stearns, and Stevens. Agassiz National Wildlife Refuge continues to be a major breeding center, as well as far west-central Minnesota, including the counties of Big Stone, Lac qui Parle, Lincoln, Stevens, and Yellow Medicine. Since the MBS reported its results, there has been an increase in the number of summer records in north-central and northeastern Minnesota.
The increase in the number of observations and the distribution of breeding season observations in Minnesota appears to reflect what is happening at the continental scale, where the species has gradually expanded its range through the Great Lakes and New England. Some of this expansion has been aided by small, local introductions, but the majority is attributed to the establishment of state and national wildlife refuges and the creation of impoundments that provided suitable nesting habitat (Henny and Holgerson 1974). In their comprehensive review of the species, LeSchack and his colleagues (1997) note that the species’ breeding range changed more during the 20th century than that of any other duck in North America. In addition to its expansion in the East, in the West it has expanded in Oregon, Washington, and British Columbia.
*Note that the definition of confirmed nesting of a species is different for Breeding Bird Atlas projects, including the definition used by the Minnesota Breeding Bird Atlas, compared with a more restrictive definition used by the Minnesota Ornithologists’ Union. For details see the Data Methods Section.