- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding resident and migrant; an increasing number of loons appear to be late migrants lingering in Minnesota through early- to mid-December. There are a few reports of overwintering birds as well. The Common Loon was a common species during the Minnesota Breeding Bird Atlas (MNBBA).
While the Common Loon is largely restricted to the boreal forests of Canada and Alaska, its breeding range also extends into the northern tier of the United States from the Pacific Northwest east to New England. Although Minnesota supports the largest U.S. breeding population south of Alaska (Figure 1), the centers of greatest abundance are found in Canada, especially in British Columbia, the Northwest Territories, Ontario, and Quebec. Figure 1 depicts the species relative abundance in the area best surveyed by the federal Breeding Bird Survey in southern Canada and the northern United States.
Assigned a Continental Concern Score of 9/20 by Partners in Flight and designated a species of Moderate Concern by the North American Waterbird Conservation Plan. The Minnesota Department of Natural Resources has designated the Common Loon a Species in Greatest Conservation Need. Officially recognized as Minnesota’s state bird since 1961.
A medium-distance migrant; winters are spent in the coastal waters of North and Central America.
Primarily small fish, secured by diving and swimming under water.
A mound of grasses, twigs, and aquatic vegetation placed on the ground near the lakeshore and often on an island.
Long considered the most iconic symbol of Minnesota’s northern wilderness, the Common Loon was actually a common resident of lakes throughout the state in the late 1800s and early 1900s. Hatch (1892) referenced the species’ abundance when he came to Minnesota in 1858, noting some of its favorite haunts near White Bear Lake, Waseca, and Minnetonka, where the species was frequently shot for sport. Roberts (1932) would later describe it as a common breeding resident throughout the state. Although it was less common in the prairie grassland regions of western Minnesota, confirmed nesting records (nests with eggs) were available from Jackson County in the southwest corner of the state, north through the prairie-forest border counties of Otter Tail and Becker, and onward to the Aspen Parklands of Polk County in the far northwest. Farther east, confirmed records were available from Hennepin (Minneapolis), McLeod, and Meeker Counties; inferred nesting records (nests, immature birds) were available from Isanti and Sherburne Counties and from Itasca State Park. Despite the Common Loon’s apparent statewide distribution, Roberts noted that numbers had declined considerably in the 40 years since Hatch first described it as abundant, due largely, as Hatch had commented, to the popularity of shooting the bird for mere sport.
If the Common Loon was indeed as widely distributed as Hatch and Roberts alleged, its range had retreated northward by the time that Green and Janssen prepared an updated account of its status in 1975; similar changes were noted in other states on the southern edge of the species’ range, including Wisconsin, Michigan, Ohio, and Pennsylvania (Evers et al. 2010). Largely absent from counties south of the Minnesota River, the species was confined to the forested counties of central and northern Minnesota by the early 1970s. Little had changed when Janssen provided another updated account in 1987 and delineated 32 northern counties where nesting had been confirmed since 1970. The only county south of the Minnesota River with confirmed nesting was Scott in the western Twin Cities metropolitan region. Hertzel and Janssen (1998) would later add an additional 6 counties to the list, all north of the Minnesota River.
Although the Common Loon’s population appeared relatively stable, increased recreational activity and shoreline development on Minnesota’s northern lakes began to raise concern about the potential impacts on Minnesota’s state bird. Significant die-offs of migrants congregating on Lake Michigan due to botulism poisoning during the falls of 1963, 1964, and 1965 added to the concern (Fay 1966). Then, in 1966, a field biologist who spent four months canoeing in the Boundary Waters Canoe Area Wilderness failed to observe a single young chick (Ream 1976).
These concerns, coupled with widespread public interest in the species, prompted the initiation of numerous studies across the state. Many efforts focused on understanding the impacts of recreational activity on nest site selection and productivity (McIntyre 1975; Ream 1976; Titus and VanDruff 1981; Valley 1987; Tischler 2001). Other studies focused on assessing regional and statewide population numbers (Hirsch and Henderson 1980; Mooty and Goodermote 1985; Mooty and Perry 1988; Mathisen 1988; McIntyre 1978, 1988; Strong and Baker 2000; Larson 2016). Today, the Common Loon is one of the most well-studied members of Minnesota’s breeding avifauna. In-depth studies have been conducted in the Boundary Waters Canoe Area Wilderness (Olson and Marshall 1952; Ream 1976; Titus and VanDruff 1981), Voyageurs National Park (Reiser 1988; Paruk et al. 2008), Itasca State Park (McIntyre 1975), and the Whitefish chain of lakes in north-central Minnesota (Valley 1987; Tischler 2001). Although at least one study demonstrated a local population decline over a 15-year interval from 1971 to 1986 (McIntyre 1988), the overwhelming conclusion of these diverse studies was that the Common Loon is an adaptable species that has maintained a stable and healthy population in Minnesota for several decades.
MNBBA participants reported 2,856 Common Loon records in 30.9% (1,528/4,941) of the surveyed atlas blocks and in 28.5% (666/2,337) of the priority blocks. Breeding evidence was gathered in 762 (15.4%) of the surveyed blocks (Figures 2 and 3; Table 1). The species was observed in 56 of Minnesota’s 87 counties and was documented breeding in 41 counties; 1 block where breeding was documented straddled 2 different counties (Scott and Dakota). This latter record was the only one located south of the Minnesota River. However, “probable” breeding records were recorded in 2 southern counties (Lyon and Sibley) and “possible” breeding records were recorded in 4 southern counties (Murray, Wabasha, Waseca, and Watonwan). Six of the counties where nesting was confirmed were not documented previously by Hertzel and Janssen (1998): Carlton, Dakota, Mille Lacs, Pine, Polk, and Swift.
Detections on MNBBA point counts were coupled with data on habitat, landscape context, and climate to generate a map of suitable Common Loon habitat in Minnesota (Figure 4). Sites with the highest suitability are located in the Laurentian Mixed Forest Province and the northern region of the Eastern Broadleaf Forest Province. Nevertheless, scattered sites are also predicted to occur throughout south-central and southwestern Minnesota and along the Mississippi River valley.
Although the Common Loon has apparently retreated from the southern counties where it may have been an uncommon resident in the early twentieth century, its distribution has remained relatively stable over the past 50 years. Comparison of the map of breeding season locations identified by the Minnesota Biological Survey (MBS) with the MNBBA distribution map actually suggests that the species has become more common in the Twin Cities metropolitan region in the past 20 years. In Anoka, Hennepin, Ramsey, Scott, Washington, and Wright Counties, records from the MNBBA were far more abundant than records from the MBS (Minnesota Department of Natural Resources 2016). The same was true, though to a smaller degree, in northwestern Minnesota.
As noted earlier, populations retreated elsewhere along the southern edge of the loon’s breeding range in areas where residential and agricultural development changed the landscape. Reports in the late twentieth century, however, suggested that recolonization of some of these areas may be underway in the northeastern United States (Evers et al. 2010). During its second breeding bird atlas, Ontario documented a small expansion in the Common Loon’s distribution in the southeastern region of the province (Cadman et al. 2007) and Michigan documented an increase in nesting reports along the southern edge of the species’ breeding distribution in the Lower Peninsula (Chartier et al. 2013).
*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.