- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding species and migrant; occasionally observed during the winter months on open water, especially Lake Superior, and may occasionally overwinter. The Bufflehead was a rare species during the Minnesota Breeding Bird Atlas (MNBBA).
The breeding distribution of Bufflehead stretches from Alaska east to western Quebec, dipping south into the United States in portions of the northwest and north-central states, including Minnesota. Highest breeding densities are restricted to regions of Alaska and western Canada. Its distribution and relative abundance in southern Canada and the United States, as depicted by the federal Breeding Bird Survey (BBS), are shown in Figure 1.
A game species, the Bufflehead was assigned a Moderate Continental Priority by the North American Waterfowl Management Plan. Partners in Flight assigned it a Continental Concern Score of 10/20.
A medium-distance migrant that winters along the Pacific coast from Alaska to Baja California, and along the Atlantic coast from Newfoundland south to northern Florida, as well as throughout the southern Great Lakes, the southern United States, and northern Mexico.
A diving duck that feeds primarily on aquatic invertebrates during the summer but also consumes seeds of aquatic plants, mollusks, and crustaceans during migration and winter.
Secondary-cavity nester that nests in tree cavities up to 0.5 to 3 m above the ground; sometimes uses nest boxes.
For many years, Minnesota was considered simply a migratory stopover for this handsome little duck as it traveled to and from its breeding range in the Canadian boreal forest. In the early 1900s, Roberts (1932) described it as a common spring and fall migrant that was on rare occasions found during the winter as well. Although he described the species as a common migrant, he also remarked that it was formerly much more abundant, “passing through the state in flocks of considerable size, while now it is usually seen in pairs or little parties of a half-dozen or so.”
At the time of his writing, there were no confirmed breeding reports in the state. He did speculate, however, that the species may occasionally nest in the Northwest Angle. Also included in his account is a brief note that Breckenridge observed a single bird on Winchell Lake, Cook County, in July 1928, suggesting that the bird might occasionally nest in this region of the state.
Fifty years later, Green and Janssen (1975) reported that the Bufflehead still had not been confirmed nesting in Minnesota. They classified it as a “casual visitant in the northern half of the state.” Single birds had been reported during the summer months in Cass, Clearwater, Cook, Douglas, Kittson, Mahnomen, Marshall, and St. Louis Counties. There also was a report of 3 birds in August 1963 in Chisholm, St. Louis County.
The first confirmed nesting report came in 1978 with a report by Minnesota Department of Natural Resources (MNDNR) wildlife manager, George Davis (Davis 1978). A brood of Buffleheads was observed on three different occasions on the East Park Wildlife Management Area (WMA) in Marshall County. Davis’s report also included a note that a colleague, area wildlife manager Jack Jensen, also reported, presumably in earlier years, broods of Bufflehead on the Roseau River WMA in Roseau County. Seven years later nesting was documented a little farther south, again in Marshall County on the Agassiz National Wildlife Refuge (Bell 1985). Since then, most nesting reports have continued to come from wetlands in Marshall County with one notable exception in 1983, when a brood was reported in Carver County (Heidel 1983). In 1998, Hertzel and Janssen added Beltrami County to the short list of counties where nesting has been confirmed.
Over the years, birders have continued to report an increasing number of summer observations from most of the counties in northern Minnesota as well as from several counties in central and south-central Minnesota (Minnesota Ornithologists’ Union 2016). But there is considerable variability in the number and distribution of reports from year to year. Despite these wide-ranging reports, Marshall County has remained the core of the species’ breeding range in the state. Following the initial report of nesting in 1985, the number of nesting pairs and young broods has continued to increase. A study initiated on the Agassiz National Wildlife Refuge (NWR) by the University of North Dakota estimated nearly 200 nesting pairs on the refuge between 2008 and 2012 (Danelle Larson, MNDNR, pers. comm. 2017). The Minnesota Biological Survey has reported only 2 breeding season locations during the course of its fieldwork: 1 each in Clearwater County and Marshall County (Minnesota Department of Natural Resources 2016).
During the MNBBA, participants reported 27 Bufflehead records from only 23 of the surveyed atlas blocks and from 11 of the priority blocks. Breeding was confirmed in 13 (0.3%) surveyed blocks (Figures 2 and 3; Table 1). The birds were observed in 10 of Minnesota’s 87 counties and were confirmed breeding in 3 counties. Fourteen of the 23 atlas blocks, including 11 of the blocks with confirmed nesting records, were from eastern Marshall County, in or adjacent to the Agassiz NWR and the Thief Lake WMA. The 2 other nesting records were from Roseau County to the north and, most surprisingly, more than 350 miles to the south, in Cottonwood County! The latter record was of a hen and brood on the Hurricane WMA and was confirmed with a photo.
The southern Minnesota breeding record may not have been such a rarity in the 1800s. Gauthier (2014) references old breeding records from New Brunswick, Maine, and the northern Great Plains that suggest the species may have ranged farther south and east of its current breeding range in the late 1800s and early 1900s. On the other hand, the species’ presence in southern Minnesota would surely have been noticed even in Roberts’s time.
*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.