- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A summer resident in the forested region of the state and a regular spring and fall migrant; may occur statewide during the winter but is most frequently observed in the south. The Brown Creeper was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).
Found from southern Alaska, east across southern Canada, south through the Pacific Northwest and the Rocky Mountains, and east across the Great Lakes states and New England. Difficult to detect, the Brown Creeper does not reach high densities anywhere within its breeding range (Figure 1).
Assigned a Continental Concern Score of 8/20 by Partners in Flight.
In many areas the species is a year-round resident. Birds that breed in the far north, however, move south for the winter, many overwintering in the U.S. interior. Birds that nest in high elevations may move to lower elevations.
Insectivore that forages primarily on tree trunks, systematically moving from the base of a tree upward.
One of the most unusual and difficult-to-locate bird nests, it is usually wedged between loose bark and the trunk of a dead or dying tree.
The Brown Creeper is a somewhat complicated species to describe. When Roberts wrote Birds of Minnesota in 1932, he characterized the Brown Creeper as a “half-hardy species” residing in “the northern evergreen forests as far south as Isanti County.” Although he classified it as a permanent resident, he noted that it was less common in the region during the winter and also an uncommon winter resident farther south. Given the difficulty of finding the species’ well-hidden nests, it is not surprising that there were only two confirmed reports: one from central Minnesota, “probably southern Crow Wing County” (1870; nest with six eggs), and one from Cook County (1930; five fully fledged young and one unhatched egg). An inferred nesting report was available from Itasca County, where adults were seen carrying food (1930).
Some summer residents in the northern regions remained into the winter months, but conditions must have been challenging for a species that depends on insect eggs and larvae for food. Commenting on those northern birds, Roberts (1932) wrote,
They are regular visitors in small numbers at winter feeding-stations where suitable food is supplied. It appears, however, that continued cold weather and perhaps a decreasing food supply take a toll from these venturesome birds that remain behind after the bulk of their kind has retreated to milder climes, for it frequently happens that, as the winter progresses, they become fewer and fewer.
Forty years later, Green and Janssen (1975) considered the Brown Creeper a regular summer resident throughout north-central and northeastern Minnesota. Documented nesting reports in Hennepin County in 1951 and 1952 (Jarosz 1952; Parmelee 1975) and in Goodhue County in 1956 (Titus and Titus 1956) led them to speculate that the species was probably a resident “throughout much of the wooded portion of the state.” They also described it as a winter visitant from Clay, Beltrami, and St. Louis Counties southward.
When Janssen (1987) prepared another updated account several years later, new breeding reports were available from Flandreau State Park in Brown County (1983) and Whitewater State Park in Winona County (1983). These reports, combined with numerous summer observations in Houston and Winona Counties, led him to conclude the species’ breeding range extended south along the Mississippi River valley to the Iowa border. In addition to the more western breeding record in Brown County, summer records were also reported in Cottonwood and Pope Counties. Since 1970, breeding records were now available from 8 counties: Aitkin, Anoka, Brown, Clearwater, Lake, Lake of the Woods, St. Louis, and Winona. Hertzel and Janssen (1998) later added 3 more counties to the list: Cook, Dakota, and Polk. Overwintering birds, Janssen (1987) noted, were most common in the east-central, south-central, and southeastern regions of the state.
Although the Minnesota Biological Survey (MBS) had yet to complete its statewide efforts, from 1987 to 2014 they collected 250 Brown Creeper breeding season observations. Perhaps most significant were the breeding season locations documented along the floodplain forests of the Minnesota River, west to Redwood County, as well as locations in the central Minnesota counties of Kandiyohi, Morrison, Stearns, and Todd (Minnesota Department of Natural Resources 2016).
MNBBA observers tallied 709 Brown Creeper detections from 10.1% (479/4,738) of the surveyed atlas blocks and from 11.6% (271/2,337) of the priority blocks. Breeding was confirmed in 28 blocks (Figures 2 and 3; Table 1). The birds were detected in 33 of Minnesota’s 87 counties and were confirmed breeding in 14 counties. Breeding records in 9 of the 14 counties were additions to the 1998 list published by Hertzel and Janssen: Carlton, Cass, Crow Wing, Goodhue, Hennepin, Hubbard, Itasca, Ramsey, and Scott. Ramsey and Scott Counties were added because 2 blocks with confirmed breeding each straddled two counties: Dakota/Scott and Dakota/Ramsey. The MNBBA failed to document Brown Creepers in the upper Minnesota River valley but did document considerably more birds than the MBS in the north-central and northwestern regions of the state and in the Twin Cities metropolitan region. Records suggest the core of the species’ breeding range, however, is in Cook, Lake, and northern St. Louis Counties.
The predicted distribution map generated using MNBBA data in combination with data on habitat, landscape context, and climate, predicts that Brown Creepers may be found in moderate breeding densities across much of the Laurentian Mixed Forest Province (Figure 4). Lower densities are predicted throughout the Tallgrass Aspen Parklands, in the northern portions of the Eastern Broadleaf Forest Province, and along the Mississippi River valley, from the Twin Cities south to the Iowa border.
Accurately assessing significant changes in the distribution and abundance of Brown Creepers has many challenges. This small, diminutive bird is well camouflaged against the tree trunks it inhabits, and its high-pitched, tinkling song is difficult to detect beyond close range. Nevertheless, the absence of reports during the summer months in southern Minnesota in the early 1900s suggested they were either absent or quite rare in abundance. Although they still are uncommon south of Crow Wing County, scattered locations in east-central Minnesota, particularly in the floodplains of the lower Minnesota River and the Mississippi River, provide suitable habitat as do extensive forest tracts located in southeastern Minnesota.
Aside from local changes in abundance due to changing habitat conditions, the only notable range expansion apparently occurred decades ago, when the species expanded south in the mid-Atlantic states (Poulin et al. 2013). In the Upper Midwest, Wisconsin has not detected any major change in distribution (Cutright et al. 2006). In Ontario the number of observations in two of their northern regions (the Northern Shield and Hudson Bay Lowlands) increased significantly between their first (1981–1985) and second (2001–2005) atlases, but the differences were thought to reflect the participation of more-skilled field observers (Cadman et al. 2007). In Michigan the species was believed to breed locally throughout the state in the early 1900s but to have later retreated from areas of the southern Lower Peninsula that were cleared for agriculture and industrial development. Populations were believed to rebound during the 1960s and 1970s when Dutch Elm disease left an abundance of dead and dying tress that temporarily provided new habitat opportunities for Brown Creepers. Biologists predicted the spread of gypsy moths could result in a similar beneficial die-off of mature trees in future years (Brewer et al. 1991). To date, at least, atlas efforts have not demonstrated any significant change in the detection of Brown Creepers in the southern 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.