Eastern Wood-Pewee

A regular summer resident and migrant, the Eastern Wood-Pewee was common during the Minnesota Breeding Bird Atlas (MNBBA).

Found throughout the eastern United States and southern Canada as far west as southeastern Alberta, western Nebraska, and central Texas. Highest densities have been found in southwestern Missouri and central Tennessee (Figure 1).

Assigned a Continental Concern Score of 10/20 by Partners in Flight.

Long-distance migrant, overwintering in northwestern and western South America.

Flying insects that are captured by sallies from a perch; occasionally gleans from foliage.

Cup nest placed on a branch of a tree or saplings in the subcanopy or canopy. Species is known to use a wide variety of deciduous and coniferous tree species.

In 1932, Roberts described the Eastern Wood-Pewee simply as “a common summer resident, breeding throughout the state.” He included nesting records from Fillmore (nest with one egg), Goodhue (nest with eggs), Hennepin (nests with eggs), Houston (several nests), Isanti (nest), and Wabasha (2 nests each with one fresh egg), all counties in the southeast. Farther north the only nest records Roberts reported were from Cass County (nest with eggs) and Itasca State Park (feeding young). He commented that the “nest is a frail but beautiful structure” but “difficult to see from the ground as it rises but little above the limb on which it rests and has the entire outside covered with bits of lichen, bark, and spider-web, like the nest of a Hummingbird.” Hence, confirmation of nesting can require a substantial effort when the nest is placed high in the canopy.

Green and Janssen (1975), more than 40 years later, similarly described the Eastern Wood-Pewee’s summer distribution, reporting that the species is a “resident throughout the state” and “frequents groves on the prairie.” Several years later, Janssen (1987) echoed the species’ statewide distribution but noted the Eastern Wood-Pewee was least common in the southwest. He confirmed nesting since 1970 in 23 counties from Rock County in the southwest to Houston County in the southeast, northwest to Pennington County and northeast to St. Louis County. Hertzel and Janssen (1998) included confirmed nesting in five additional counties for a total of 27 counties but excluded Clearwater County, which was previously included by Janssen in 1987.

The Minnesota Biological Survey (MBS) recorded 1,932 breeding season locations in its county surveys. The MBS included Eastern Wood-Pewee breeding observation locations from every county in the state the survey has sampled except Clay County in western Minnesota.

The MNBBA identified 3,018 breeding records for the Eastern Wood-Pewee from 40.3% of all surveyed blocks (1,911/4,746) and 55.2% of priority blocks (1,289/2,337) (Figures 2 and 3; Table 1). Nesting was confirmed in 43 counties, probable nesting in 38 counties, and possible nesting in an additional 5 counties (Figure 3; Table 1). The only county with no records was Pipestone County in the southwestern corner of the state. The extensive distribution of the Eastern Wood-Pewee observed during the MNBBA and the number of confirmed nesting records are a strong tribute to the diligence of Minnesota’s atlas observers, since documentation of nesting activity is not an easy task.

The probability map for the Eastern Wood-Pewee emphasizes the statewide distribution of the species but especially its presence in the broad ecotone between the coniferous forests in the northeast and the agricultural/grasslands of the western, southwestern, and southern portions of the state (Figure 4). Highest densities were predicted in the Eastern Broadleaf Forest Province, and more specifically in the Hardwood Hills Subsection and in floodplain forests of the Mississippi River and many of its tributaries.

The overall breeding distribution of the Eastern Wood-Pewee likely has not changed substantially in Minnesota over the past 100-plus years. With almost a 50% loss of forests in the state, its breeding population has undoubtedly declined. McCarty’s (1996) review of the Eastern Wood-Pewee in North America also described no changes in this species’ distribution since those described by Bendire in 1895.

Both Michigan and Wisconsin, during their breeding bird atlases, reported that Eastern Wood-Pewees were breeding throughout their states (Cutright et al. 2006; Chartier et al. 2013). Michigan did not detect changes from its first to its second atlas, whereas Ontario noted a few regions where the Eastern Wood-Pewee had declined from its first atlas (1981–1985) to its second atlas (2001–2005). Overall there was no change across the province (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.

McCarty (1996) summarized that the Eastern Wood-Pewee breeds in virtually every type of wooded community, including both deciduous and coniferous forest types. Roberts (1932) suggested the species has a “preference for oak woodlands but [occurs] commonly everywhere throughout the state.” Extensive counts of this species in the national forests of northern Minnesota and Wisconsin (n = 3,207 detections) during the breeding season indicated a significant preference for oak forest cover types but also substantial use of red pine, upland hardwoods, and beech-maple-birch forests cover types (Niemi et al. 2016). Pewees avoid lowland coniferous forests and open habitats such as those recently logged. Forest habitats with open subcanopies that allow space to sally for flying insects are favored (Niemi and Hanowski 1984, 1992) (Figure 5).

During the MNBBA point counts, the Eastern Wood-Pewee was primarily found associated with pine forests and secondarily in oak forests (Figure 6). Detections were also noted in pine-oak barrens and northern hardwoods.

Many studies have emphasized that Eastern Wood-Pewees are not sensitive to the size of forest fragments (Robbins et al. 1989). For instance, Blake and Karr (1987) found the species in forest sizes that ranged from 1.8 to 600 ha, and Stauffer and Best (1980) observed its use of wooded riparian habitats as narrow as 20 m wide.

Rosenberg et al. (2016) estimated a North American population of 6.7 million breeding adults, and Partners in Flight Science Committee (2013) estimated 180,000 in Minnesota. The MNBBA estimated a population of about 1.3 million breeding adults in Minnesota (95% confidence interval of 1.14 – 1.84 million) . The MNBBA counts were based on a larger sample size than that used by Partners in Flight, plus Partners in Flight’s estimate for Minnesota was primarily based on the proportion of potential habitat in the state.

The federal Breeding Bird Survey (BBS) population trends for Minnesota indicated a decline of 0.41% per year that was approaching significance from 1967 to 2013, but recent trends from 2005–2015 were stable (Figure 7). Trends in Michigan were similar to those in Minnesota. However, data from Ontario and Wisconsin and all routes completed in the United States, Canada, and survey-wide showed significantly declining trends from 1966 to 2015 (Sauer et al. 2017). Partners in Flight estimated a decline in the population of 44% from 1970 to 2014 (Rosenberg et al. 2016). The overall pattern of population trends across North America for the Eastern Wood-Pewee indicates widespread declines, including in most of Minnesota, although the northwestern region shows a slight increase (Figure 8).

The regional trend in Minnesota’s national forests was significantly declining from 1995 to 2016 by 1.1% per year (Figure 9). In the Chippewa National Forest the significant, declining trend was 1.0% per year based on a sample size of 91 forest stands, but in the Superior National Forest, where the species is less common (n = 30 forest stands), the trend was insignificant.

Population density estimates for the Eastern Wood-Pewee are sparse in Minnesota. The National Forest Bird (NFB) monitoring program provided a general estimate of abundance in the Chippewa and Superior National Forests. Mean densities observed were 1.8 pairs per 40 ha in the Chippewa National Forest, and 0.4 pairs per 40 ha in the Superior National Forest. These densities represent the generally higher populations in north-central Minnesota compared with the northeastern region (Niemi et al. 2016). In the Chippewa National Forest, densities in oak forests, one of the species’ most favorable habitats, averaged 2.5 pairs per 40 ha. Densities were also high in mature red pine forest stands, averaging 3.4 pairs per 40 ha in the Chippewa Forest, and 2.3 pairs per 40 ha in the Superior National Forest.

The Eastern Wood-Pewee has received no official designation as a species of concern in Minnesota or nationally. Partners in Flight assigned the species a moderate Continental Concern Score of 10/20 in their North American conservation assessment. The greatest concern is the large population decline of this species over the past 45-plus years. At present, however, the species’ population is still relatively large and widespread in eastern North America. Loss of forested habitat in Minnesota over the past 150 years has certainly decreased its overall population.

Collisions with communication towers were considered to be a minor source of mortality. McCarty (1996) cited pesticides and subsequent reductions in insect prey as possibly associated with reduced populations of the Eastern Wood-Pewee. Decalesta (1994) documented negative effects on its breeding population from artificially high deer populations in the northeastern United States due to excessive browsing in the understory.

The Eastern Wood-Pewee has been documented as tolerant of habitat fragmentation because of its use of edges and small forest fragments (Blake and Karr 1987; Robbins et al. 1989). Langham et al. (2015) and the National Audubon Society (2015), in their review of North American bird species susceptible to climate change, did not identify the Eastern Wood-Pewee as vulnerable.

The status of Eastern Wood-Pewee’s wintering populations in South America is not well known; the species is difficult to identify on the wintering grounds because of its lack of vocalizations.

Population levels of the Eastern Wood-Pewee will need to be continually monitored, and additional studies of its nesting success in Minnesota would be desirable.