Yellow-bellied Flycatcher

A regular breeding resident and migrant; the Yellow-bellied Flycatcher was uncommon during the Minnesota Breeding Bird Atlas (MNBBA).

Widely distributed across Canada from Labrador to British Columbia to the tree limit, and in the United States restricted to the northern regions of the Upper Midwest and the northeastern New England states. Highest densities are found in Labrador, Nova Scotia, and northern Minnesota (Figure 1).

Assigned a Continental Concern Score of 9/20 by Partners in Flight.

Long-distance migrant; winters in southern Mexico and Central America.

Flying insects that are caught in the air and gleaned from foliage.

On the ground in moss, roots, or thick vegetation.

Roberts (1932) never reported a nest of the Yellow-bellied Flycatcher but considered it a summer resident in northern portions of the state. The totality of his records indicated it was a fairly rare species. This may have been an indication of a lack of coverage in appropriate habitat and difficult identification, especially by observation. Roberts recorded the following observations, which he said, “show that it is a summer resident in northern Minnesota”: Aitkin County (female in breeding condition in June 1897), Itasca State Park (behavior on July 9, 1917, indicated a nest or young nearby), Lake County (1 collected on July 15, 1914), eastern Marshall County (brood of young being fed by adults on July 10, 1900), and St. Louis County (1 collected on June 14, 1894).

Roberts (1932) summarized its distribution as follows: “The records for the northern part of the state are not numerous but show that it is widely distributed during the breeding-season from the eastern border of the Red River Valley to Lake Superior, as far south as Itasca Park and Aitkin County.” He also dismissed a statement by Hatch (1892) that this species spends the summer in the vicinity of Minneapolis.

In 1975, Green and Janssen described a breeding distribution that was similar to what Roberts (1932) reported. Their boundaries included northeastern and north-central Minnesota as far south as Bruno in Pine County, southern Aitkin County, and west to Clearwater and Marshall Counties. They cited confirmed breeding records only from northern Lake County. Janssen (1987) restated the distribution described in Green and Janssen (1975) and emphasized that the species was “best represented in northern Cook, Lake, St. Louis, Lake of the Woods, Koochiching, and Itasca Counties.” Janssen (1987) and Hertzel and Janssen (1998) both included 3 confirmed nesting records from Aitkin, Cook, and Koochiching Counties since 1970.

The Minnesota Biological Survey (MBS) thus far has recorded 635 breeding season locations during intensive county surveys. Locations were widely spread across northern Minnesota; the vast majority were distributed from southern Beltrami County to Cook County. The spatial extent of their locations ranges south to Mille Lacs, northern Morrison, and Pine Counties, west to eastern Becker County, and northwest to Marshall, Pennington, and Roseau Counties. Note that the MBS has not yet completed surveys in northern Beltrami, Koochiching, or Lake of the Woods Counties.

The MNBBA provided a solid snapshot of the current breeding distribution with 889 records of the Yellow-bellied Flycatcher (Figure 2). The species was recorded in 9.4% (444/4,735) of all surveyed blocks and in 9.6% (225/2,337) of priority blocks (Figure 3; Table 1). Nesting was confirmed from 5 counties: Beltrami, Cass, Itasca, Lake, and St. Louis. In addition, probable breeding was identified in another 8 counties: Aitkin, Carlton, Cook, Hubbard, Koochiching, Lake of the Woods, Pine, and Roseau. Possible nesting extended south to Kanabec and Mille Lacs Counties and west to Clearwater and eastern Marshall Counties.

The breeding distribution is slightly larger than what had been previously described, extending southward to Kanabec and Mille Lacs Counties. Many recent studies, especially in the lowland and upland coniferous forests of northern Minnesota, have indicated relatively high populations of the Yellow-bellied Flycatcher in the Agassiz Lowlands Subsection and in northeastern Minnesota (e.g., Niemi and Hanowski 1984; Warner and Wells 1984; Niemi et al. 2016; Bednar et al. 2016; and Zlonis et al. 2017).

The probability map for the Yellow-bellied Flycatcher predicts the primary distribution in the northeastern and north-central regions of the state (Figure 4). Highest densities are predicted in the Red Lake Peatland north of Upper Red Lake and a broad region from southwestern St. Louis County to northeastern Lake and Cook Counties.

Gross and Lowther (2011) suggested that the Yellow-bellied Flycatcher distribution has remained relatively stable in North America since the early 20th century. They commented on the loss of breeding habitat in the southern fringes of the species’ range in Canada and from southern Wisconsin. These changes have largely been due to logging, drainage of bogs, and agricultural development. Kumlien and Hollister (1951) stated that “Thure Kumlien took a nest with four eggs in the Bark River woods, Jefferson County, June 7, 1860 and two nests at a later date in 1863 and 1864.” Jefferson County is in the second tier of counties in southeastern Wisconsin. Interestingly, Kumlien and Hollister also stated that this species was “not as rare in Wisconsin as early writers have made us believe.”

Roberts (1932) stated that the Yellow-bellied Flycatcher was not found south of Aitkin County during the breeding season, and his documents indicate that he and others spent considerable time in the area of Mille Lacs and Pine Counties. Limited suitable habitat likely occurred south of these regions in Minnesota. However, Cadman et al. (2007) in Ontario questioned whether “atlasers’ increased familiarity with the songs and calls of the species” contributed to finding the species more widespread during their second breeding bird atlas. It remains unknown if vocal identification issues confounded observations during the early years of settlement in southern and central Minnesota.

*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.

Yellow-bellied Flycatcher haunts have been broadly described as boreal conifer forest and peatlands, bogs, and muskeg (Gross and Lowther 2011). Roberts (1932) reported that all of the reports of this species were “found in dense spruce, tamarack, and arbor vitae swamps.” These observations correspond well with those from Minnesota’s national forests, which included over 3,200 breeding season observations. In the Chippewa and Superior National Forests, Yellow-bellied Flycatchers were significantly associated with black spruce–tamarack and mixed swamp conifer forest cover types (Niemi et al. 2016). Lesser numbers were found in upland aspen-spruce-fir and jack pine forest cover types (Figure 5).

Recent breeding bird counts in the Agassiz Lowlands Subsection of northern Minnesota identified Yellow-bellied Flycatchers in most lowland conifer habitats, except those dominated by white cedar or recently logged habitats (Bednar et al. 2016; Zlonis et al. 2017). The species’ ubiquity in this region was illustrated by its presence in 68% of 130 forest stands sampled in the Agassiz Lowlands (Zlonis et al. 2017).

The Yellow-bellied Flycatcher’s preference for bogs and to a lesser extent both upland and lowland coniferous forested areas was reinforced by detections during the MNBBA point counts (Figure 6).

Rosenberg et al. (2016) estimated a North American breeding population of 14 million adults. In Minnesota, the MNBBA estimated a breeding population of approximately 680,000 breeding adults (95% confidence interval of 567,000 – 1,683,000) . In contrast, the Partners in Flight Science Committee (2013) estimated a population of only 170,000 breeding adults in Minnesota. The discrepancy in these estimates is likely due to the under-sampling of many of the habitats in northern Minnesota where this species occurs. This includes the extensive Red Lake Peatland region and the Boundary Waters Canoe Area Wilderness, which are not sampled by the federal Breeding Bird Survey (BBS), because they are roadless areas. Hanowski and Niemi (1995) had previously noted that many species that occur in wetland-associated habitats, such as lowland coniferous forests, are under-sampled on roadside counts. Even though the MNBBA used roadside counts, many of the roadless areas were also surveyed with point counts.

The BBS population trend for Minnesota was unreliable because of too little coverage and a mean of less than 1 bird per route. Trends were also unreliable for both Michigan and Wisconsin. The Yellow-bellied Flycatcher population trend for the Boreal Hardwood Transition region, an area that includes a substantial part of northern and northeastern Minnesota, indicated a stable population from 1966 to 2015 (Figure 7). However, the species’ population trend was significantly increasing in Ontario (3.54% per year), in Canada (2.30%), and survey-wide (2.26%) over this same time period. The only significantly declining trends reported for the species by the BBS from 1966 to 2015 were from the northeastern United States and eastern Canada: New Hampshire, Vermont, and New Brunswick.

Partners in Flight reported a potential 119% increase in the North American breeding population of the Yellow-bellied Flycatcher from 1970 to 2014 (Rosenberg et al. 2016). This trend is in contrast with the findings of Ralston et al. (2015), who reported significant declines in this species’ population based on nine different, regionally specific point count data sets. These data sets spanned the spruce-fir forest communities from the northeastern to the midwestern United States. They suggested that species such as the Yellow-bellied Flycatcher that are spruce-fir obligates and do not extensively use other habitat types were most associated with declining populations.

Breeding bird data from 1995 to 2016 in the Chippewa and Superior National Forests indicated mixed trends. Yellow-bellied Flycatchers were deemed stable with an insignificant trend in the Chippewa National Forest (1.69% per year), but significantly declining in the Superior National Forest (2.32% per year) (Figure 8). The species’ regional trend also was significantly declining, at 1.31% per year based on samples from 113 forest stands. The species was more common in the Superior, so that trend dominated the overall trend. These results, which were incorporated in the Ralston et al. (2015) analysis, indicate basic differences in the trends of the Yellow-bellied Flycatcher. These differences likely are due to the census methods used and regional variation in populations of this species. Future trend results or further research are likely the only solution to resolving these conflicting results.

Mean densities of the Yellow-bellied Flycatcher in the Chippewa and Superior National Forest from 1995 to 2012 were 2.0 and 4.9 pairs per 40 ha, respectively (Niemi et al. 2016). Mean density estimates within mature black spruce–tamarack habitats in the Chippewa and Superior National Forests were 6.9 and 12.7 pairs per 40 ha, respectively. In mixed swamp conifer forest cover types of the Chippewa and Superior National Forests, the mean densities were 6.3 and 13.8 pairs per 40 ha, respectively. In the Agassiz Lowlands Subsection, mean densities ranged from 2.2 to 15.7 pairs per 40 ha in northern white cedar and black spruce–tamarack bogs, respectively.

Yellow-bellied Flycatchers have a moderately low conservation score of 9/20 by Partners in Flight and therefore do not have any specific designations of concern in Minnesota or nationally (Rosenberg et al. 2016). The species is secure in Canada, where its primary breeding population is found (Dunn et al. 1999).

The lack of extensive coverage of many parts of northern Minnesota forests in the 1800s, early 1900s, and up to the 1970s prohibits statements about changes in the population or distribution of this species in the state. Recent counts in Minnesota’s national forests, by the MBS, and in the Agassiz Lowlands Subsection indicate that the species is likely more common than previously thought, but this is unlikely due to increases in its population. Historical and recent declines in the coniferous forest of Minnesota (Jaako Pöyry Inc. 1992) have likely contributed to overall declines in the population of this species over the past 150 years. Although these changes may have gone undetected previously, recent increases in logging activity in northern Minnesota coniferous forests may be contributing to recent declines in selected areas, such as the Superior National Forest.

Yellow-bellied Flycatchers have been recorded at tower kills, but impacts on the overall population are unknown (Gross and Lowther 2011). Neither Longcore et al. (2013) nor Loss et al. (2014) noted the species as having high mortality at towers or buildings and residences.

Continued threats to the Yellow-bellied Flycatcher include (1) increased logging, especially in lowland coniferous forest; (2) the loss of tamarack forests due to the eastern larch beetle in Minnesota and lack of knowledge on their recovery; and (3) climate change, which will likely create better conditions in Canada than currently exist in Minnesota. The latter will require longer migration distances between the species’ winter and breeding ranges. Langham et al. (2015) and the National Audubon Society (2015) listed the species as “climate threatened” due to a projected 83% loss of its current summer range by 2080. Like that of the moose and other boreal species, its existence in Minnesota is under long-term threat.

Gross and Lowther (2011) commented on historical changes that have occurred on the Yellow-bellied Flycatcher’s wintering grounds in Mexico and Central America. How the species’ wintering areas changed with the massive landscape alterations during the Mayan cultures is unclear, but currently its winter range is under continued threat from loss of forested habitat due to agricultural development.