Scientific Name: Dendroica fusca
Nest Type: Cup
Nest Location: Coniferous trees; 20-50'
Clutch Size: 4-5; avg. 4
Food: Insects
Foraging Guild: Foliage gleaner, hawk, hover and bark glean
The Blackburnian Warbler is a summer breeding species in north central regions of Minnesota (Janssen 1987). Its breeding range is limited to the extreme north
central and northeastern United States, south into the northern Appalachians, and southeast Canada (Peterson 1980). It arrives in Minnesota in early May through
early June after spending the winter in a region of Central and South America from Costa Rica to Peru (Peterson 1980). Fall migration begins in mid-August with
late departing individuals staying until early October (Janssen 1987).
Over most of its breeding range, the Blackburnian Warbler is highly associated with mature coniferous trees (Green and Niemi 1978, Collins et al. 1982). Also,
Green (1991) classified this species as primarily associated with contiguous coniferous forests. Its habitat requirements in Ontario included mature stands of
conifers including white pine, white and black spruce, hemlock, and red pine in that order of importance (de Kiriline Lawrence 1953). In its range within the
Appalachians the species will inhabit pine-oak vegetation (Harrison 1975). However, when it is found in deciduous forest areas, the species is primarily associated
with mature coniferous trees found within these areas (Morse 1989). The presence of mature, tall conifer trees that represent more than 50% of the canopy cover
are important vegetation characteristics of its breeding habitat (Titterington et al. 1979).
In Minnesota the species is found most abundantly in a variety of lowland and upland, mature coniferous forests. Highest densities in the Chippewa National Forest
in 1991 and 1992 were recorded in pole size red and jack pine stands (3.1 to 3.4 pairs/40 acres) (Hanowski and Niemi 1991a). The species also occupied several
habitat types in the Superior National Forest, but was most abundant in mature white pine and upland spruce (4.0 to 4.3 pairs/40 acres) (Hanowski and Niemi
1991b). Niemi (1977) also found it in relatively high abundance in mature coniferous forests.
The Blackburnian Warbler, like many species that have high-pitched songs, primarily sings from the top of tall trees (Ficken and Ficken 1962). They nest in conifer
trees and place their nest from 5-85 feet above the ground (Roberts 1932, Harrison 1975). The nest usually contains 4 to 5 eggs and is well concealed in foliage or
Usnea moss (Harrison 1975). The species forages in tree tops near the tips of conifer foliage (Morse 1989). The primary food sources are invertebrates and
densities of the species may be affected by spruce budworm outbreaks (Kendeigh 1947, Morris et al. 1958). However, because Bay-breasted and Cape May
Warblers numbers increase during budworm outbreaks, Blackburnian Warblers may be limited due to interspecific competition with these species (Kendeigh 1947).
Numbers of Blackburnian Warblers recorded on Breeding Bird Survey routes in Minnesota have remained essentially the same over the past 25 years (Janssen
1990). However, because of the species high dependency on mature coniferous trees it will be most affected by overall changes in the distribution and abundance of
these mature conifers.
