Blue-headed Vireo

A regular summer resident and migrant. The Blue-headed Vireo was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).

Found throughout northeastern North America, south in the Appalachian Mountains to northeastern Mississippi, and northwest across Canada to British Columbia (Figure 1). The highest densities are observed in Nova Scotia and north-central Ontario.

7/20 Continental Concern Score by Partners in Flight.

Short- to long-distance migrant, the species overwinters in the southeastern United States, Mexico, and Central America.

Insects and some spiders gleaned from foliage.

Cup nest suspended from fork usually at the end of a conifer shrub or sapling branch.

Roberts (1932) primarily knew the Blue-headed Vireo from his time at Itasca State Park and described it overall as a “frequent summer resident of the coniferous forests.” He reported nesting records from 1886 in Becker County (nest with eggs), at Itasca Park in 1919 and 1928 (nests with eggs), and one from Itasca County in 1930 (young ready to leave the nest). Overall he described its breeding distribution as south to Lake Mille Lacs, west to Itasca Park, and northeast to Cook, Lake, and St. Louis Counties.

More than forty years later, Green and Janssen (1975) described a similar breeding distribution in northeastern and north-central Minnesota. They reported breeding observations from Carlton County but stressed that its western boundary was “poorly known” and likely extended only to Itasca State Park. They added confirmed nesting in Hubbard, Lake, and St. Louis Counties. Janssen (1987) also reinforced the species’ primary distribution in northeastern and north-central Minnesota and included confirmed nesting since 1970 in 8 counties: Aitkin, Cass, Clearwater, Cook, Crow Wing, Hubbard, Lake, and St. Louis. He also noted summer observations from Beltrami and Roseau Counties. Later Hertzel and Janssen (1998) removed Clearwater County from the list of confirmed nesting since 1970.

During nest searches in Pine County in 1996, Pirjo and Dr. Markku Kuitunen of the country of Finland found a nest of the Blue-headed Vireo. This observation was gathered as part of a research project on the Least Flycatcher at the Natural Resources Research Institute at the University of Minnesota–Duluth. Unknown to them at the time, this is the most southerly confirmed nesting of the species in Minnesota.

The Minnesota Biological Survey included 355 breeding season locations of the Blue-headed Vireo and further solidified its primary breeding distribution in northeastern and north-central regions from Clearwater to Cook County. However, they also included many breeding observation locations from Carlton County, at least 5 locations from Pine County, and 1 location in northern Mille Lacs County.

The MNBBA included 915 breeding season records of the Blue-headed Vireo, including many from Cook and Lake Counties (Figure 2). These records also extended its possible breeding range to Kittson and Marshall Counties in the northwest as well as westward to Becker, Polk, and Wadena Counties. The species was recorded in 10.9% (514/4,734) of the surveyed atlas blocks and 13.2% (309/2,337) of priority blocks (Figure 3; Table 1). The MNBBA added confirmed nesting in Beltrami and Lake of the Woods Counties, plus evidence of probable nesting in Koochiching and Roseau Counties. It is likely that the Blue-headed Vireo nests throughout the northern region of Minnesota and as far northwest as coniferous trees are present.

Roberts (1932) noted a June 4, 1873, observation by Coues from Pembina on the Red River, at the border of North Dakota and Minnesota. This date also could represent a late migrant. Regardless, habitats along the Red River and other suitable habitats are very rare or no longer exist in many of these western counties. Similarly, many potential coniferous forests in its southwestern or southern range in Minnesota have been greatly reduced and converted to agricultural or urbanized areas.

Cutright et al. (2006) cited observations in the early 1900s from southern areas of Wisconsin and range retractions northward. However, during the Wisconsin breeding bird atlas from 1995 to 2000, nesting was confirmed in Calumet and Waukesha Counties. Waukesha County is south of the Minnesota and Iowa border, while Calumet County is equivalent in latitude to Winona County. Perhaps the unusual observation in 1983 from Houston County cited by Janssen (1987) should signal further scrutiny along the southeastern counties in Minnesota. In their review of the Blue-headed Vireo in North America, Morton and James (2014) emphasized that the species has been recolonizing places where they formerly occurred in the nineteenth century. In these areas reforestation of conifers has been implemented in the midwestern United States, such as in Wisconsin, Illinois, Michigan, and the province of Ontario.

*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.

Blue-headed Vireo breeding haunts are described as evergreen forests with spruce, hemlock, and pine or often associated with deciduous growth with alder or willow in the understory (Morton and James 2014). In Minnesota, the species primarily occurs in coniferous forests (Niemi and Pfannmuller 1979; Green 1995) (Figure 4).

The National Forest Bird (NFB) Monitoring Program included 1,731 records during the breeding season between 1995 and 2010 (Niemi et al. 2016) in the Chippewa and Superior National Forests. Observations have occurred in many forest cover types, but it has been found most abundantly and most frequently in black spruce-tamarack forests. Additional cover types commonly used include pine forests (jack, red, and white) and mixed swamp conifer forests comprised of white cedar, spruce, and black ash. In the extensive lowland conifer forests of the Agassiz Lowlands Ecological Subsection, the Blue-headed Vireo was uncommon. This species was most often found in mixed black spruce-tamarack forest types (Bednar et al. 2016).

The MNBBA also indicated wide use of coniferous-associated habitats, primarily bogs, upland coniferous forests, pine forests, and lowland coniferous forests (Figure 5).

The Partners in Flight program (Rosenberg et al. 2016) estimated a global population of 13 million breeding adults; in a previous document, they estimated 110,000 breeding adults in Minnesota (Partners in Flight Science Committee 2013). Estimates from the MNBBA were 4 times greater at over 400,000 breeding adults. However, like many of the uncommon or rare species, the variability in Minnesota breeding population estimates were relatively high. Comparatively, Minnesota still has a relatively small portion of the species’ global population.

The federal Breeding Bird Survey (BBS) trend in Minnesota was unreliable, but estimates for the Boreal Hardwood Transition Region indicated a significantly increasing population of 3.57% per year from 1966 to 2015 (Figure 6). Using data from the BBS, Rosenberg et al. (2016) suggested an overall 200% increase in the breeding population from 1970 to 2014! The North American trends for the Blue-headed Vireo illustrate increasing populations throughout the species’ breeding range, with the exception of its extreme northwestern distribution in Canada (Figure 7).

In contrast, data from the NFB program indicated a non-significant trend from 1995 to 2016 and a definite downward trend from 2005 to 2016 (Figure 8). Despite substantial increases in many parts of the species’ range, details from patterns of change in BBS trends from Minnesota indicated a large declining trend in north-central Minnesota (e.g., in the Chippewa National Forest) and only moderate increases in northeastern Minnesota (Figure 7). Coverage in the national forests during the NFB program was greater than during the BBS in which the BBS had a mean of less than 1 detection per route per year. This discrepancy in estimates of species trends had previously been identified and discussed by Niemi et al. (2016, Table 12). In general, the species is uncommon throughout the forests of Minnesota. Breeding populations may be locally and regionally variable and difficult to reliably detect.

Overall mean population density estimates for the Chippewa and Superior National Forests were similar, with 1.7 and 1.5 pairs/40 ha, respectively. Mean population density estimates within specific forest cover types varied considerably within these forests.

Partners in Flight (Rosenberg et al. 2016) estimated a low overall continental concern for the Blue-headed Vireo of 7/20. Given its current population size and its substantially increasing population throughout many parts of North America, there is little current conservation concern. Its population would be susceptible to substantial increases in logging activity of intermediate and mature coniferous forest cover types. Reductions in its population were predicted under moderate and high harvesting scenarios in Minnesota (Niemi and Hanowski 1992). However, these scenarios have never come to fruition, and coniferous forest cover types have remained stable or have increased (e.g., Niemi et al. 2016, Figure 13). The recent decline of the species in the NFB program deserves closer scrutiny and continued monitoring.

Morton and James (2014) reported low numbers of the species observed in collisions with towers or buildings, suggesting that the species does not appear to be overly sensitive to mortality from human structures. In its review of climate sensitivity for over 500 bird species, Langham et al. (2015) and the National Audubon Society (2015) did not include it as a species of concern. This is likely due its current high population and wide distribution in North America, plus the potential breeding habitat available to the north in Canada.