- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular permanent resident in northern forested areas; frequent fall migrant along the North Shore of Lake Superior and south and west of its breeding range. Common Ravens were common during the Minnesota Breeding Bird Atlas (MNBBA).
Widely distributed across the northern and western United States, throughout Canada and Alaska, plus southward at higher elevations in the Appalachian Mountains (Figure 1). The highest densities are found in Nevada, western Utah, and southern California.
Assigned a Continental Concern Score of 6/20 by Partners in Flight.
Omnivorous, forages on carrion, insects, grains, fruit, and garbage.
Highly variable; cliffs, trees, buildings, or wherever there is a suitable substrate.
According to Roberts (1932), the Common Raven has had a highly variable and dubious distribution in the state. His basic summary states the species as a “once common, or even locally abundant, winter visitant in northern Minnesota as far south as Otter Tail and Wadena counties.” Most accounts by Roberts were of fall and winter observations, including those in the late 1800s in Hennepin, Pipestone, and Sherburne Counties. He also described it as common around lumbering camps, fishing stations, and “pineries” and even a nuisance in 1876–1877 about hunting camps in Otter Tail and Wadena Counties. In 1895, it was labeled as “numerous in winter as Crows are now in the summer.”
Roberts never recorded a nest of this species in the state, but forest rangers told him that it nests on cliffs in the boundary lakes of Saganaga and Gunflint as well as about Frear Lake in Cook County. Summer observations were so remarkable that he included sightings, such as at Cass Lake and Grand Rapids, Itasca County, in August 1916; three were seen in northern Itasca County on July 12, 1928; three were seen in eastern Pine County in July 1919; and one was seen near Eagle Mountain, Cook County, on July 6, 1922. In Roberts 1936 revision, he summarized a letter from Warden C.E. Cooke who had observed a nesting pair of Ravens on Drywood Island, Rainy Lake, St. Louis County in which he was “quite sure” it was in 1929. He also reported an additional observation of a Raven two miles north of Duluth by Frank Craighead, Jr. in July 15, 1935.
Roberts (1932, 1936) concluded that “the raven is one of our disappearing birds and may be approaching extinction in the state.” He never mentioned any reasons for its disappearance but recognized that many were shot or caught in wolf traps.
Green and Janssen (1975) described it as a resident in the north-central and northeastern regions. Most numerous in the Superior National Forest, it was not known in Itasca State Park until the 1960s, but it was found as far south as Mille Lacs and Pine Counties. The authors documented confirmed nesting in Carlton, Cook, Lake, and St. Louis Counties, plus inferred nesting in Koochiching County. They described its winter distribution as common in the northern regions in the 1800s and rare from about 1900 to the 1940s but increasing since the 1950s.
Janssen (1987) also commented on its range expansion since the 1950s, especially “westward and very slowly southward.” He included confirmed nesting in 8 counties since 1970: Cook, Koochiching, Lake, Lake of the Woods, eastern Marshall, Roseau, St. Louis, and Wadena. Hertzel and Jansen (1998) further documented its expansion with 4 additional nesting records confirmed since 1970 in Aitkin, Beltrami, Isanti, and Pine Counties.
The Minnesota Biological Survey (Minnesota Department of Natural Resources 2016) documented extensive breeding season locations throughout northern and north-central Minnesota. Surveyors detected 555 records extending westward to Becker, Clearwater, Kittson, Mahnomen, and Polk Counties. In addition, they recorded locations southwest to Todd County and south to Chisago and Mille Lacs Counties.
Breeding detections were extended even further by the MNBBA, which included 2,162 records (Figure 2). Confirmed nesting was recorded from 226 blocks, including confirmed county records from Becker, Benton, Cass, Crow Wing, Hubbard, Itasca, Kittson, Mille Lacs, Morrison, Norman, Pennington, Polk, Red Lake, and Washington Counties (Figure 3; Table 1). In total, this species was observed from 27.7% of all surveyed blocks in the state (1,318/4,763). Probable nesting was also documented from 127 blocks, including south to Chisago County and west to Otter Tail County. One southeastern breeding season observation was also made in Winona County.
The probability map based on the MNBBA data point counts emphasized a widespread distribution across northeastern, north-central, and northern Minnesota (Figure 4). Slightly lower populations were predicted south to northern Isanti and Washington Counties, west to eastern Becker and northeastern Otter Tail Counties, and northwest to Kittson County. Pockets of its presence were also predicted in the Hardwood Hills Ecological Subsection in western Minnesota where possible and probable nesting records from the MNBBA existed.
The current distribution of the Common Raven represents a substantially broader breeding distribution than what has been suggested for the past 100–150 years. The species has made a remarkable recovery since Roberts’s comment in 1932 that it is “approaching extinction.”
Boarman and Heinrich (1999), in their review of the Common Raven in North America, identified “shooting, poisons, baited traps, and disappearance of bison” as primary reasons for changes in its distribution, especially on the prairies. They point out that its disappearance in the New England states was largely attributed to deforestation, conversion of land to agriculture, and increases in American Crow populations. Houston (1977) noted that the species began to inhabit cities in Saskatchewan, where they were losing their fear of man and began foraging on garbage. Boarman and Heinrich also pointed out that “raven sightings along roads increased by more than 7,600% between 1968 and 1992” in the California’s Central Valley.
Cutright et al. (2006) emphasized that the Common Raven was apparently widespread from north to south in Wisconsin at the time of European settlement. However, between 1860 and 1890 the species disappeared from southern Wisconsin and declined in northern regions. The authors primarily cited increased conversion of forests to agriculture as a reason for decline in the southern regions. Breeding distribution during the Wisconsin breeding bird atlas (1995–2000) documented confirmed nesting as far south as Marquette County, which is equivalent in latitude to Minnesota’s most southeastern counties of Houston and Winona. Hence, breeding distributions in Wisconsin paralleled and even exceeded recent Minnesota southern extensions of its breeding range. Chartier et al. (2013) in Michigan cite similar examples of retractions and recovery of the Common Raven populations during the 1900s.
The decline and recovery of the Common Raven appears to be due to a variety of factors. Declines in the late 1800s and early 1900s were likely associated with extensive human persecution via shooting, poisoning and trapping, conversion of vast areas of habitat to agricultural and urban landscapes, and possibly interactions with American Crows, especially at carrion feeding sites. The recovery was likely associated with reductions in human persecution with the passage of the Migratory Bird Treaty Act of 1918, loss of fear of man with additional feeding (garbage and roadkill) and nesting opportunities (e.g., towers, poles, bridges, and abandoned buildings), and in some cases with reforestation.
*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.