Ruddy Duck

A regular breeding species and migrant. Occasionally reported during the winter months, especially in open-water locations in southeastern Minnesota. Most birds are late-fall migrants, but there are some reports of overwintering birds. The Ruddy Duck was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).

Although the Ruddy Duck’s breeding range is extensive, stretching from central Canada south through much of the western United States and northern Mexico, the core of its breeding distribution is restricted to the Prairie Potholes of the northern Great Plains (Figure 1).

A game species, the Ruddy Duck has been designated a Moderately Low Priority at the continental level by the North American Waterfowl Management Plan. It has been assigned a Continental Concern Score of 10/20 by Partners in Flight.

A short- to medium-distance migrant; most northern populations winter in the central and southern United States and in Mexico. Populations in the Caribbean islands, Mexico, and in portions of the western United States, are year-round residents.

A diver that feeds primarily on a variety of aquatic invertebrates; small amounts of aquatic vegetation and seeds also are consumed.

A platform nest placed over shallow water; sometimes constructed atop a muskrat house or coot nest.

In 1932 Roberts wrote that in years past the Ruddy Duck was “an abundant breeding bird in all the larger rush-grown and weed-grown sloughs of southern and western Minnesota.” By 1900, however, its numbers were significantly reduced. It “was to be found only locally here and there, for just what reason is not quite clear.” Unlike the many other waterfowl species that were considered tasty treats by the early settlers and slaughtered by the thousands year-round, Roberts noted that the Ruddy Duck was largely ignored. As a result, he was unsure what factors were responsible for the species’ rather dramatic decline. But as the populations of other, more favored species fell, the Ruddy Duck became more popular among hunters. Indeed, the species’ habit of diving rather than flying when disturbed made it quite easy to harvest large numbers during migration, likely contributing to the speed at which populations plummeted (Brua 2002).

By the 1920s, with the recent passage of hunting regulations and the federal Migratory Bird Treaty Act of 1918, Roberts and his colleagues began to observe greater numbers of the Ruddy Duck. As population numbers recovered, the species slowly began to reoccupy much of its former breeding range, from Lincoln County in the southwest corner of the state to Grant and Big Stone Counties in west-central Minnesota, north to Kittson County on the Canadian border. In 1929, a game warden in west-central Minnesota reported that “he never saw the Ruddy when he first went to Grant County years ago, but that now it is everywhere” (Roberts 1932). Despite the numerous reports of nesting pairs in a number of localities, at the time of his writing Roberts only had confirmed breeding records (nests with eggs) from 3 counties: Hennepin, Jackson, and Kittson (Roberts 1932).

More than forty years later, Green and Janssen (1975) summarized the species’ distribution in similar terms, noting that it occurred throughout western Minnesota and east as far as the Twin Cities. East of its primary breeding range in northern Minnesota, the authors added nesting records from Cass and Clearwater Counties. Their account included a reference to a 1964 report by the Minnesota Department of Natural Resources summarizing results of waterfowl surveys conducted in the early 1960s (Lee et al. 1964). At the time, the Ruddy Duck comprised only 2% of the state’s breeding waterfowl population.

A few years later, Janssen (1987) delineated 26 counties where nesting had been confirmed since 1970, including 1 record in 1982 and 1 in 1983 from Moose Lake in Carlton County. In 1998, Hertzel and Janssen (1998) delineated 31 counties where nesting had been confirmed since 1970, but 2 counties identified earlier by Janssen were not included: Clearwater and Cass. Carlton County remained the most eastern nesting locality.

Fieldwork conducted by the Minnesota Biological Survey documented a total of 134 breeding season locations for the Ruddy Duck. All but 2 of the records were within the species’ primary range in western and central Minnesota. The 2 outliers included 1 record along the Mississippi River in Winona County and 1 record in northeastern Cass County (Minnesota Department of Natural Resources 2015).

During the MNBBA, participants reported 257 Ruddy Duck records from 4.2% (199/4,741) of the surveyed atlas blocks and from 4.5% (105/2,337) of the priority blocks. Breeding evidence was confirmed in 26 (0.5%) of the surveyed blocks (Figures 2 and 3; Table 1). The species was observed in 46 of Minnesota’s 87 counties; 4 counties were included because of blocks that straddled county lines: Brown, Dakota, Goodhue, and Scott. Breeding was confirmed in 18 counties. Nearly all of the records were within the species’ primary range. No records were documented in northeastern or north-central Minnesota. The farthest east the Ruddy Duck was reported was in Dakota, Goodhue, Olmstead, and Ramsey Counties; breeding was confirmed as far east as Hennepin County in south Minneapolis and Freeborn County in southern Minnesota.

Since the Ruddy Duck recovered from its population decline in the late 1800s and early 1900s, its status has remained relatively unchanged. Its breeding distribution in Minnesota is essentially identical to that reported in the 1930s, but its relative abundance among the 18 duck species that regularly breed in the state has slipped slightly. Whereas the Ruddy Duck comprised 2% of breeding ducks in the early 1960s, it averaged only 0.6% of the total number of breeding ducks reported from 2011 through 2015 (Cordts 2015). During the MNBBA, the species ranked eleventh among the 18 duck species in terms of the total number of records reported.

Elsewhere, the species’ breeding distribution in North America has shown “no substantial changes,” with the exception of a reduction in the extent of its breeding in the Great Lakes region (Brua 2002). More recent work in the Great Lakes, however, suggests the species is at least stable to increasing, particularly in the western Great Lakes region. In Wisconsin, the population estimate from 1965 to 1970 was 400 birds; by 1972 it had risen to 3,200 birds. Records during Wisconsin’s first atlas appeared to confirm a relatively stable population centered primarily in the Horicon National Wildlife Refuge in south-central Wisconsin (Cutright et al. 2006). Michigan documented an increase in the number of counties where the Ruddy Duck was observed between the state’s first atlas (9 counties, 1982–1988) and its second (20 counties, 2002–2008) (Chartier et al. 2013). Since the first confirmed nesting in Ontario in 1949, the species’ breeding range has expanded to include most of the southern region of the province (Cadman et al. 2007). Despite significant differences in the number of occurrences throughout different regions of the province between Ontario’s first (1981–1985) and second atlases (2001–2005), the overall probability of detection throughout the province did not change. Cadman and his colleagues (2007) attribute much of the species’ recent expansion to its use of sewage lagoons and to the lagoons’ high concentration of midge larvae, one of the species’ primary food items (Brua 2002; Zimmerling 2006).

*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.

The Ruddy Duck utilizes a variety of wetland habitats, including large wetland complexes, reservoirs, small stock ponds, and sewage lagoons (Brua 2002; Cadman et al. 2007). The primary requirements are extensive beds of emergent vegetation and scattered open water areas that allow enough room for birds to become airborne (Figure 4). This chunky little bird needs a relatively long distance to run on the water and gain enough momentum to take flight (Brua 2002). Field studies in South Dakota reported that 60% of breeding pairs were found on wetlands that were greater than 4.9 ha; 30% were found on wetlands that ranged from 2.0 to 4.8 ha; and 10% were found on small wetlands from 0.8 to 1.9 ha (Evans and Black 1956). In both South Dakota and North Dakota, the majority of nesting pairs preferred semipermanent wetlands (Kantrud and Steward 1977; Ruwaldt et al. 1979).

In a study of habitat use and nesting success of ducks nesting in shallow water in west-central Minnesota, Maxson and Riggs (1996) found Ruddy Duck nests were located in water that averaged 67.5 cm in depth and were placed, on average, 36.6 m from the shoreline. Nests were usually well concealed within dense stands of emergent vegetation.

Although the Ruddy Duck is widely distributed throughout much of western North America, approximately 86% of the breeding population occurs in the Prairie Potholes of the northern Great Plains and the Canadian Prairie provinces (Figure 1) (Batt et al. 1989). As a result, the Traditional Survey Area of the Waterfowl Breeding Population and Habitat Survey conducted by the U.S. Fish and Wildlife Service and the Canadian Wildlife Service, which is designed to cover the Prairie Potholes, includes much of the species’ breeding range and provides a reasonable index of population trends. Data collected on the Ruddy Duck, however, are not widely reported but are available for retrieval on the U.S. Fish and Wildlife Service’s website. From 1987 through 2015, the data show a slow but steady increase from approximately 400,000 birds to over 800,000 (Figure 5). Baldassarre (2014) reported that the average annual population size from 1955 to 2011 in the Traditional Survey Area was approximately 452,000 individuals, although the numbers fluctuated widely from year to year. More recently, the 2012 update to the North American Waterfowl Management Plan (NAWMP 2012) estimated the mean size of the Prairie Potholes population at 630,000 birds from 2002 to 2011, while the continental population was estimated at 1.2 million birds.

The other long-term data set available on Ruddy Duck populations is the federal Breeding Bird Survey (BBS). Survey-wide, the BBS data show a nonsignificant, slow population increase of 0.94% per year since the survey began in 1966, increasing to 2.66% per year from 2005 to 2015 with wide fluctuations (Figure 6). Although these data are not statistically significant, they have a high degree of reliability at the continental scale (Sauer et al. 2017).

In Minnesota, waterfowl survey efforts are not statewide but instead focus on the most productive waterfowl habitats, which are located in central and western Minnesota. Once again, the population shows wide fluctuations and even suggests a downward trend (Figure 7). The Ruddy Duck is one of the last birds to arrive on its breeding grounds each spring (Baldassarre 2014). Because waterfowl surveys are timed to correspond more closely with the nesting phenology of more favored species, such as the Mallard and the Blue-winged Teal, many Ruddy Ducks may still be en route to their final breeding grounds when the survey is conducted. Wide fluctuations, therefore, may be more a reflection of the vagaries of migration than the status of nesting populations.

Because populations are considered relatively stable and the Ruddy Duck is not a highly valued species by waterfowl hunters, the North American Waterfowl Management Plan (2004) has ranked the species a Moderately Low Priority. It has been assigned a moderate Continental Concern Score of 10/20 by Partners in Flight (2017). Its relatively small population size, combined with concerns regarding its wetland breeding habitat, contributed to the moderate score.

As noted earlier, when populations of highly prized waterfowl species plummeted in the late 1800s and early 1900s, hunters took aim instead at the Ruddy Duck, resulting in a significant population decline. Since then, the numbers of other waterfowl species have rebounded and the Ruddy Duck is, once again, a species not favored by most hunters. During the 2015 season, only 25,727 birds were harvested in the United States, comprising less than 1% of the total duck harvest (Raftovich et al. 2016). That same year, 1,030 birds were harvested in Minnesota, comprising 0.2% of Minnesota’s total duck harvest.

The Ruddy Duck is not a focus of any targeted conservation effort. The North American Waterfowl Management Plan has not even established a population goal for the species (Brua 2002). But like all wetland-dependent species in Minnesota, it will benefit from several conservation initiatives that have been launched in recent years, including Minnesota’s Long Range Duck Recovery Plan (Minnesota Department of Natural Resources 2006) and the Minnesota Prairie Conservation Plan (Minnesota Prairie Plan Working Group 2011). Both programs have established aggressive goals for protecting, restoring, and actively managing wetlands in the western region of the state. If these efforts prove successful, they will have multiple benefits to Minnesota’s Ruddy Duck population.

Besides known concerns regarding the protection and restoration of critical nesting habitats, other factors that influence population levels of the Ruddy Duck are less well studied. During the winter months, the majority of birds concentrate in a limited number of key sites across the country, so impacts to these areas can significantly influence populations nationwide. High levels of several contaminants, including mercury, cadmium, lead, and zinc, have been found in birds sampled at two key wintering sites, the Chesapeake Bay and the San Francisco Bay (Baldassarre 2014; Brua 2002). Oil spills in these coastal areas also are a concern.

Finally, as for all wetland-dependent species that depend on the Great Plains Prairie Pothole Region, climate change may significantly impact future populations. Although the Ruddy Duck has been assigned a low vulnerability to climate change, wetlands in this critical nesting region are projected to decline by two-thirds as temperatures increase (North American Bird Conservation Initiative 2010). The future of this unique little member of Minnesota’s waterfowl community should not be taken for granted.