- Minnesota Breeding Bird Distribution
- Breeding Habitat
- Population Abundance
- Literature Cited
A permanent, year-round resident, the Barred Owl was an uncommon species during the Minnesota Breeding Bird Atlas (MNBBA).
Largely a species of the Eastern Deciduous Forest (stretching into western Canada and the Pacific Northwest), the Barred Owl is sparsely distributed throughout its breeding range (Figure 1).
Assigned a Continental Concern Score of 7/20 by Partners in Flight.
Non-migratory; winter influxes of northern birds may be related to prey availability.
Carnivorous, feeding primarily on small mammals, small birds, reptiles, amphibians, and invertebrates. Hunts from an elevated perch.
Secondary cavity nester that primarily uses natural cavities or the hollowed-out tops of tree snags; also nests in old platform nests built by hawks and crows or squirrel nests.
The Barred Owl has long been recognized as a common, year-round resident of Minnesota’s forested regions. Roberts (1932) wrote that its preferred habitat was the “deep, dark forests, though it may occasionally be found in more open places and even in the sparse groves of timber bordering the prairie streams and lakes.” Confirmed nesting records (nests with eggs or young), however, were sparse for such a wide-ranging species and limited to four counties in southeastern Minnesota: Hennepin, Houston, Scott, and Wabasha.
Green and Janssen (1975) had little to add when they provided an update on the species’ status many years later. There were breeding records from the forested regions of the state, but no Barred Owls had been documented nesting further west despite their occasional presence. Janssen’s 1987 update included a map that defined the species’ breeding range as the Laurentian Mixed Forest and Eastern Broadleaf Forest Ecological Provinces of northern and eastern Minnesota. The map excluded all but the Minnesota River valley in western Minnesota. It also identified 21 counties where nesting had been confirmed since 1970. Only one record, in Brown County, occurred west of the forested regions. In 1998 Hertzel and Janssen published an updated map of nesting records confirmed since 1970. They deleted one of the counties identified by Janssen (Itasca) and added five new ones, including three in the Prairie Parklands: Blue Earth, Kandiyohi, and Nicollet.
Barred Owl breeding season observations by the Minnesota Biological Survey added further evidence that the species’ breeding range is confined largely to the forested region of the state and along the Minnesota River valley into western Minnesota. Among a total of 73 records to date, only 7 were within the Prairie Parklands region (Minnesota Department of Natural Resources 2017).
Long considered a non-migratory, sedentary species, the Barred Owl does undertake some movement in the winter months. Hatch (1892) believed birds in southern Minnesota moved further south during severe winters compared with northern birds. He occasionally received specimens from northern lumber camps during extremely severe winters, which led him to believe that northern populations were more sedentary than southern populations. Roberts (1932) made no mention of migratory movements, but Green and Janssen (1975) noted that winter influxes of birds occasionally occur, especially in northern Minnesota. Janssen (1987) specifically commented on the increased number of observations reported during the winters of 1983–1984 and 1984–1985, primarily in the southern half of the state, suggesting that the species may be “partially migratory.” In his comprehensive review of North American owls, Johnsgard (1988) also commented that the northernmost populations of Barred Owls “are probably semi-migratory, depending upon prey availability.” Whether or not these are truly migratory movements—with the birds returning the following spring—or one-time dispersals is unclear.
During the MNBBA, observers tallied a total of 756 Barred Owl records distributed in 11.6% (558/4,794) of the atlas blocks that were surveyed and in 11.3% (264/2337) of the priority blocks. Breeding was confirmed in 59 blocks (Figures 2 and 3; Table 1). The birds were reported in 66 of Minnesota’s 87 counties and were confirmed breeding in 28 counties. Of these, 15 are additions to the map published by Hertzel and Janssen (1998): Carlton, Carver, Dakota, Dodge, Goodhue, Itasca, Lake, Lake of the Woods, Le Sueur, Lyon, Morrison, McLeod, Scott, Steele, and St. Louis. The overwhelming majority of blocks with Barred Owls were reported in the Laurentian Mixed Forest and the Eastern Broadleaf Forest Ecological Provinces.
Overall, the species’ distribution is remarkably similar to what it was nearly one hundred years ago. Mazur and James (2000) note that the major change in the species’ North American distribution in the twentieth century was its expansion west into the boreal forests of Canada and the Pacific Northwest. Factors responsible for the movement were unclear but are believed to include fire suppression, increasing forest age, and the establishment of shelterbelts in the northern Prairie Provinces of Canada. Each of these changes would provide more suitable habitat for the Barred Owl.
States and provinces in the Upper Midwest that have conducted two atlases also have found that the species’ distribution has remained largely unchanged over the years. The number of birds, however, have increased or decreased in response to habitat changes at the landscape level or as a consequence of more targeted owl surveys, such as in Ontario (Cadman et al. 2007; Iowa Ornithologists’ Union 2017; Chartier et al. 2013; Rodewald et al. 2016).
Although the Barred Owl’s distribution in Minnesota appears unchanged, its relative abundance has changed significantly. In Roberts’s day, the Eastern Screech-Owl was considered the most abundant owl in the state. Today, the screech-owl is far outnumbered by both the Barred Owl and Great Horned Owl. The latter two species, nearly identical in abundance during the MNBBA, were nearly 12 times more common than the screech-owl.
*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.