- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A regular breeding resident and migrant; some birds occasionally linger into the early winter months. The Vesper Sparrow was a common species during the Minnesota Breeding Bird Atlas (MNBBA).
Broadly distributed from eastern British Columbia south to northern California, Nevada, northern Arizona, and New Mexico, and east through the northern Great Plains and the northern half of the eastern deciduous forest region. The core of its breeding range is largely west of the Mississippi River, in the western Great Plains states, and in the southern Prairie provinces (Figure 1).
Assigned a Continental Concern Score of 11/20 by Partners in Flight.
A partial migrant; northern populations winter in the southern United States and Mexico.
A ground-foraging omnivore that feeds on arthropods and seeds.
An open-cup nest usually placed on the ground at the base of a clump of grasses, forbs, or shrubs. Sometimes a small ramp leading up to the nest is present, as well as a canopy of bent-over vegetation.
In the late 1800s and early 1900s, Roberts (1932) considered the Vesper Sparrow to be a common summer resident south of the densely forested region of the state, noting that it actually increased in abundance as one moved north from the Iowa border. Although not common in northern Minnesota, he wrote that “every clearing, old burned-over area, wind-fall, or cut-over region, has its considerable quota of Vesper Sparrows.” It was, he wrote, “one of the commonest and most generally distributed of Minnesota birds.” Confirmed nesting reports (nests with eggs) were available from Anoka, Crow Wing, Hennepin, Isanti, Polk, and Sherburne Counties and from Itasca State Park, Cass Lake, and Leech Lake. Inferred nesting reports (nests only) were reported from Goodhue and Lake of the Woods Counties.
Green and Janssen (1975) reported that the Vesper Sparrow was a resident throughout Minnesota yet was least common in the northeast, where nesting was documented only as far as St. Louis County. Janssen (1987) further noted that the species was largely absent throughout Cook, Lake, and St. Louis Counties and uncommon in the north-central region as well. His distribution map eliminated the entire Arrowhead region as well as Carlton County and portions of Koochiching, Itasca, Aitkin, and Pine Counties. Within the species’ primary breeding range, he identified 20 counties where nesting had been confirmed since 1970. Hertzel and Janssen later added another 11 counties to the list.
Beginning in the late 1980s, the Minnesota Biological Survey reported a total of 490 breeding season locations for the Vesper Sparrow. Common throughout the southern and western regions of the state, the species was least abundant in the Laurentian Mixed Forest Province, where the majority of records were found along the province’s western border with the Eastern Broadleaf Forest Province. A few records, however, were found as far east as Itasca and St. Louis Counties (Minnesota Department of Natural Resources 2016).
MNBBA participants reported 2,768 Vesper Sparrow detections from 33.6% (1,601/4,761) of the surveyed atlas blocks and from 51.9% (1,213/2,337) of the priority blocks. Breeding evidence was documented in 109 (2.3%) atlas blocks (Figures 2 and 3; Table 1). The species was reported from every county except Cook and was confirmed breeding in 47 counties (1 block straddled 2 counties, Dakota and Rice). Twenty-five of the counties were additions to the list Hertzel and Janssen published in 1998. Included among the MNBBA records were 2 breeding detections in central St. Louis County, 1 in Babbitt and 1 from the tailings basin of the old LTV Steel Mining Company. Widely distributed and quite common in western Minnesota, the Vesper Sparrow was least common in extreme southeastern Minnesota, in the Twin Cities metropolitan region, and in east-central, north-central, and northeastern Minnesota.
The MNBBA’s predicted distribution map demonstrates the species’ strong association with the agricultural regions of western and southern Minnesota (Figure 4). High breeding densities are predicted in southwestern Minnesota and along the Red River valley, gradually decreasing east through the Eastern Broadleaf Forest Province and the Laurentian Mixed Forest Province. In the latter, the species is only predicted to be present in low to moderate breeding densities along the very southern and western borders of the province and in the open landscape of the Iron Range in St. Louis and Itasca Counties. Forested floodplains appear to be one of the few areas in western Minnesota where densities are predicted to be lower.
In the past one hundred years, the distribution of the Vesper Sparrow has changed very little. It remains uncommon in the densely forested landscape of northeastern and north-central Minnesota. Yet in areas where forest cover has been lost due to industrial or residential development, the species has found suitable habitat. The breeding records at the old LTV tailings basin are an example. The grassland cover planted on the reclamation site now provides ideal nesting habitat for this adaptable species.
Historically, the Vesper Sparrow has made similar moves throughout its breeding range. As forests in New England and southern Canada were cleared, the species gradually expanded into regions where populations are now declining. Many of the farmlands have been abandoned and vegetation has either succeeded to forest or has been cleared for development (Jones and Cornely 2002). This general pattern has been observed throughout much of the eastern United States.
Changes in the Vesper Sparrow’s distribution and abundance in Ontario are an excellent example. Biologists speculated that if the species was present prior to European settlement, “it was restricted to scattered natural openings caused by wildfires and to areas where Aboriginal peoples cleared and burned forests for corn fields, making ephemeral pockets of grassland habitat” (Cadman et al. 2007). As forests were cleared for development, numbers increased and populations expanded. But many lands cleared in the 1800s have been converted from farmland to urban and residential developments or have succeeded to mature forests. Although these changes have contributed to the species’ decline, more intensive agricultural practices are considered the primary culprit. As a result, Ontario witnessed a 29% decline in Vesper Sparrow populations between the first atlas, conducted from 1981 to 1985, and the second atlas, conducted from 2001 to 2005. The species’ primary breeding range has also shifted to the south and west (Cadman et al. 2007).
*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.