- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding resident and migrant, the Indigo Bunting was a common species during the Minnesota Breeding Bird Atlas (MNBBA).
The summer breeding range of the Indigo Bunting stretches across southeastern Canada and south throughout the eastern United States, from the eastern Great Plains to the Atlantic and Gulf coasts. Scattered populations are present in the southwest United States. The bunting reaches its highest breeding densities in many of the south-central states, including Missouri, Arkansas, Tennessee, Kentucky, southern Illinois, and southern Indiana (Figure 1).
Assigned a Continental Concern Score of 9/20 by Partners in Flight.
A medium- to long-distance migrant that winters in Central America, the Caribbean, and occasionally in northern South America.
An omnivorous diet of insects and seeds. Foraging occurs primarily on the ground but also on the foliage of shrubs and small trees.
An open-cup nest usually located within 1 m of the ground and placed within a shrub, small tree, or tall forb, often in a brushy field or a woodland edge or clearing.
Roberts (1932) provides a lengthy description of the distribution of the Indigo Bunting in Minnesota in the late 1800s and early 1900s. He described the bunting as found in nearly all corners of the state and most abundant in the southeast, especially in counties bordering the Mississippi River north as far as the town of Red Wing in Goodhue County. “Farther north it becomes less frequent but has been found along the Red River as far north as Norman and Marshall counties; at Leech Lake, Cass County; in Itasca County; along the north shore of Lake Superior from Duluth to Grand Marais; and in the interior of Cook County.” Although the species had yet to be found in Kittson and Roseau Counties, in the far northwestern corner of the state, documentation of its breeding status in Winnipeg suggested it was, at the least, a rare resident in these counties as well. The bunting could also be found in small woodland groves that dotted the southwestern prairie region. Within the forested counties of north-central and northeastern Minnesota, it was largely restricted to “clearings and burnt-over areas.” Roberts never found it at Itasca State Park even though he spent several summers there. Nesting was confirmed (nests with young or eggs) in Fillmore, Goodhue, Hennepin, Houston, and Wabasha Counties; nesting was inferred (nest and adult carrying food) in Lake and Lake of the Woods Counties.
Years later, both Green and Janssen (1975) and Janssen (1987) simply commented that the Indigo Bunting occurred throughout the state but was “most numerous in the southeastern, south-central, east-central, and central regions” (Green and Janssen 1975). Janssen included a statewide distribution map that identified 18 counties where nesting had been confirmed since 1970. Hertzel and Janssen (1998) later added 4 counties to the list.
The Minnesota Biological Survey has reported 913 breeding season observations of Indigo Buntings (Minnesota Department of Natural Resources 2016). Although the vast majority of records were in the Eastern Broadleaf Forest Province and in the southern counties of the Laurentian Mixed Forest Province, a surprising number of records were reported along the Minnesota River valley and throughout the southwest corner of the state, where earlier observers reported it as relatively uncommon. No doubt the planting and maturation of many farm shelterbelts contributed to the species’ abundance in the region.
During the MNBBA, observers reported 2,590 Indigo Bunting records in 32.9% (1,563/4,756) of the surveyed atlas blocks and in 45.7% (1,068/2,337) of the priority blocks. Breeding evidence was gathered in 67 blocks (Figures 2 and 3; Table 1). The species was found in all 87 Minnesota counties and was confirmed breeding in 38 counties (2 blocks where breeding was confirmed were on the borders of Scott and Dakota Counties and two blocks were on the borders of Scott and Carver Counties). The species remained most abundant in the Eastern Broadleaf Forest Province and in the southern and western regions of the Laurentian Mixed Forest Province. Indigo Buntings were least abundant in northeastern Minnesota, in Koochiching County, and in the far northwestern counties, stretching from Polk to Kittson.
The MNBBA predicted distribution map predicts the highest breeding densities occur in scattered pockets in southeastern, south-central, and east-central Minnesota, including along the lower Minnesota River valley (Figure 4). Moderate densities are predicted throughout much of central and southern Minnesota and along the tributaries of the Red River in the northwest. The species is predicted to be absent to rare across northeastern and far north-central Minnesota.
In the past 100 years, the breeding distribution of the Indigo Bunting has changed very little in Minnesota. It occurred throughout the northern forest region in Roberts’s time but is likely more common and widespread now that industry, agriculture, and residential development have fragmented the forest landscape from Brainerd north to Duluth, Grand Rapids, and Bemidji. Elsewhere within its breeding range, the species expanded north into Canada, particularly into the Maritime Provinces in the 1970s, and west into California, Arizona, and New Mexico beginning early in the 20th century. During this same time period, it also expanded south along the Florida peninsula (Payne 2006). More recently, states and provinces that have conducted two breeding bird atlases have documented little change in the species’ distribution or abundance. These include Ontario, Michigan, Ohio, and South Dakota (Cadman et al. 2007; Chartier et al. 2013; Drilling et al. 2016; Rodewald et al. 2016).
*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.