White-breasted Nuthatch

A permanent resident; the White-breasted Nuthatch was a common species during the Minnesota Breeding Bird Atlas (MNBBA).

Found throughout most of the United States and southern Canada. It is scarce in the central Great Plains states, except in woodlots and riparian habitats, and largely absent from the Great Basin and Sonoran Desert. It does not reach high densities anywhere within its range, although it is more abundant in the east-central United States from the Great Lakes south to Missouri, Arkansas, Tennessee, West Virginia, and Virginia (Figure 1).

Assigned a Continental Concern Score of 6/20 by Partners in Flight.

Permanent resident. Occasional reports of local movements of birds. For example, individuals will show up at feeders along the North Shore during the winter months even though they have not been present in the surrounding woods during the summer months (J. Green, pers. com.). Biologists speculate that these may represent young of the year moving outside of densely populated areas, but further investigation is needed.

Bark forager. Feeds primarily on insects during the summer. Seeds are important at other times of the year and are frequently cached within crevices and furrows in tree bark. Common visitor to bird feeders.

Secondary cavity user; nests typically placed in old woodpecker holes or natural cavities. Occasionally they will excavate to enlarge a hole but rarely excavate an entire new cavity on their own.

In the early 20th century, Roberts (1932) commented that the White-breasted Nuthatch was a common breeding resident “throughout the state wherever there is timber,” but it was more abundant in southern Minnesota. He went on to add that it “is one of our most familiar little birds, ever at home and busy among the shade trees of the city and the monarchs of the forest.” Confirmed nest records (nests with eggs) were available from Hennepin, Meeker, Scott, and Sherburne Counties. Inferred nesting records were reported in Marshall County (young out of nest) and Wadena County (nest building).

Many years later, Green and Janssen (1975) noted that the White-breasted Nuthatch was a permanent resident throughout the state but “very scarce and local during the breeding season in the northeastern region,” where confirmed breeding reports were lacking. Several years later, when Janssen (1987) provided an updated account of the species, nesting had been documented in St. Louis County (1974), in Lake County (1982), and in 27 other widely dispersed counties since 1970. Hertzel and Janssen (1998) later added 4 more counties to Janssen’s (1987) breeding distribution map.

The Minnesota Biological Survey has reported a total of 961 breeding season locations. Records were widely distributed throughout the state in all but the most intensively cultivated regions. Widely scattered records were also reported in the Arrowhead region of northeastern Minnesota, becoming increasingly scarce east of St. Louis County to the Canadian border (Minnesota Department of Natural Resources 2016).

White-breasted Nuthatches were found statewide during the MNBBA with a total of 2,793 records. Observers reported the birds in 36.0% (1,707/4,744) of the surveyed atlas blocks and in 46.7% (1,091/2,337) of the priority blocks. Breeding was confirmed in 209 blocks (Figures 2 and 3; Table 1). The birds were observed in all 87 counties and were confirmed breeding in 56 counties (Rice County was included because 1 block with confirmed nesting straddled both Rice and Dakota Counties). Confirmed and probable records were least frequent in southwestern Minnesota; no confirmed or probable records were reported in Cook County. In the Arrowhead region and far north-central Minnesota (i.e., Koochiching and Lake of the Woods Counties) the Red-breasted Nuthatch surpasses the White-breasted Nuthatch in abundance.

The MNBBA predicted breeding distribution map (Figure 4) predicts that the species is moderately abundant in the Eastern Broadleaf Forest Province. Throughout the state, scattered pockets of abundance also are predicted along major rivers, including the Mississippi River, the Minnesota River, and major drainages throughout southern and northwestern Minnesota. The species is also predicted to be moderately abundant throughout the western and southern reaches of the Laurentian Mixed Forest Province.

As Roberts (1932) wrote nearly 100 years ago, the White-breasted Nuthatch is a common species wherever woodlands can be found. Although it remains least common in the most heavily cultivated regions of the state, as well as in far northeastern and north-central Minnesota, it likely is more abundant in the northern forest region than it was a century ago. As the old-growth pine stands have declined and the landscape has become more developed, the forests have become more fragmented and more dominated by aspen-birch. These changes likely provided more opportunities for the deciduous-loving White-breasted Nuthatch to move farther into the densely forested landscape of northern Minnesota.

Elsewhere in its breeding range, few large-scale changes in distribution have been noted (Grubb and Pravosudov 2008). In Michigan, the species was considered rare in the extensively forested Upper Peninsula in the first half of the 20th century. However, during both of the state’s breeding bird atlases, White-breasted Nuthatches were widely distributed throughout the Upper Peninsula (Chartier et al. 2013). The number of blocks where they were reported during the second atlas (2002–2008) increased by 6% above the number reported during their first atlas (1983–1988). In Ontario, the probability of detecting White-breasted Nuthatches increased by 19% between the first (1981–1985) and second atlas (2001–2005), and the species’ range also expanded to the north. Milder winters and the popularity of winter bird feeding were thought to be responsible for the province-wide increase (Cadman et al. 2007). In Wisconsin, present-day populations are considered possibly larger than they were historically, but the species’ statewide distribution has remained unchanged (Cutright et al. 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.

An inhabitant of mature forests, White-breasted Nuthatches prefer hardwood stands, often with closed canopies and open understories (Figure 5; Danz et al. 2007). Mixed deciduous-coniferous stands also are used. However, as the amount of conifers increases in the landscape, White-breasted Nuthatches decrease in abundance, and Red-breasted Nuthatches increase. Green and Niemi (1978) commented that in the northern part of its range, in the Superior National Forest, the species is found in sites with tall (30 m) supercanopies and with sparse shrub and ground cover.

Extensive monitoring  work in the four national forests in northern Minnesota and Wisconsin demonstrated that White-breasted Nuthatches have an overwhelming preference for upland oak stands followed by upland hardwoods and lowland hardwoods (Niemi et al. 2016). Habitat data collected within 200 m of MNBBA point counts where White-breasted Nuthatches were detected demonstrated a strong preference for oak forests (Figure 6).

In addition to occurring in extensive forest landscapes, White-breasted Nuthatches are a regular species wherever large, mature hardwood trees are present, including city parks, suburban woodlots, and along riparian corridors in otherwise agricultural landscapes. Overall, the species showed some preference for woodland edges (Peck and James 1987).

Although White-breasted Nuthatches are common in small woodlot settings, studies suggest that reproductive success is higher in tracts that are larger in size. One early study suggested a minimum area requirement of 2 ha, noting that larger sites up to 10 ha were preferred (Galli et al. 1976). More recently Doherty and Grubb (2002) documented only 35% survivorship in tracts that were 5 ha in size but 65% survivorship in tracts that were 35 ha or larger.

The configuration and adjacency of small forest patches may be another important factor influencing habitat selection and reproductive success. Although the species shows some preference for woodland edges, a study in Ohio (Grubb and Doherty 1999) demonstrated that White-breasted Nuthatches were likely to use fragmented woodlot stands only if they were separated by less than 200 m from open habitats.

Using data from the federal Breeding Bird Survey (BBS), biologists recently estimated the size of the North American population of White-breasted Nuthatches at 9.4 million breeding adults, nearly 1 million more than the 2013 estimate (Rosenberg et al. 2016). In 2013, Minnesota’s statewide population estimate, using the same BBS data, was 300,000 adults, or 3.6% of the continental population (Partners in Flight Science Committee 2013). An updated statewide estimate is closer to 350,000 individuals.

Although they can be found statewide, White-breasted Nuthatches do not reach particularly high breeding densities anywhere in the state or elsewhere in their breeding range. In Minnesota an average of 1 to 2 nuthatches are detected per BBS route each year. Survey-wide, the average is only 1 bird per route. Nevertheless, Minnesota’s Eastern Broadleaf Forest Province, where the birds are particularly abundant, is within the Prairie Hardwood Transition Region, which supports some of the highest breeding densities in North America, including an average of 3 to 4 birds per BBS route (Sauer et al. 2017).

Local breeding densities ranged from 4 to 40 breeding pairs per 40 ha in southern Ontario to as low as 1.2 to 1.6 pairs per 40 ha in Missouri (Grubb and Pravosudov 2008). On the Chippewa National Forest in north-central Minnesota, the average breeding density was 0.6 pair per 40 ha; on the Superior National Forest in northeastern Minnesota the average was only 0.07 pair per 40 ha. By comparison, the average density of Red-breasted Nuthatches on the Chippewa was 2.8 pairs per 40 ha, and 3.1 pairs per 40 ha on the Superior (Niemi et al. 2016).

Survey-wide, BBS data also revealed a steadily increasing population of White-breasted Nuthatches, with a significant average annual increase of 1.71% per year from 1966 to 2015 (Sauer et al. 2017). The increase is nearly identical in Minnesota, averaging 1.84% per year (Figure 7). A similar increase of 0.88% per year has been documented on the Chippewa National Forest from 1995 to 2016 (Figure 8). Across North America, biologists estimated the population has experienced a cumulative increase of 124% since 1970 (Rosenberg et al. 2016). Factors responsible for this remarkable increase have not been delineated, but the increase is widespread in much of the eastern United States. The availability of mature shade trees in residential communities throughout North America and the ever-growing popularity of bird feeding are likely major contributors.

The White-breasted Nuthatch is not a conservation priority species. Overall, its large and increasing population and its wide distribution indicate that the species is faring reasonably well. The absence of significant threats to its habitat also contributes to its status. It has been assigned a relatively low Continental Concern Score of 6/20 by Partners in Flight (Rosenberg et al. 2016).

Because the White-breasted Nuthatch is dependent on mature trees with sufficient cavities or in a decayed condition, forest management practices that retain dead and decaying mature trees, particularly mature birch and aspen trees with signs of fungal heart rot, are important to the species’ continued health. No doubt its demonstrated preference for oak forests in northern Minnesota reflects in part its dependence on acorns for its winter diet, so maintaining large, mature oaks in forests throughout the state is also important. In more urban/suburban and agricultural settings, protection of tracts of public lands that are sufficiently large (> 10 ha) and connected is another important practice.

Although the 2010 “State of the Birds” report on climate change (North American Bird Conservation Initiative 2010) rated the White-breasted Nuthatch has having a low vulnerability to warming temperatures, a more recent analysis by the National Audubon Society suggested the threat may be larger than originally thought. In a comprehensive review of 588 North American birds Audubon biologists classified the Nuthatch as a “climate threatened” species, predicting that by the year 2080 it could lose 78% of its current summer habitat, resulting in a significant northward shift of populations (National Audubon Society 2016; Langham et al. 2015).  In the long-term it could eventually replace its near relative, the Red-breasted Nuthatch, in Minnesota’s northern forests. This handsome, acrobatic little bird likely will remain a very common and favorite bird among homeowners who enjoy feeding birds for many years to come.