page_title: Barred owl
section_title: Birds
hierarchical_section_title: Barred owl / Dietary biology / Birds
caption_attribution_description: Hermit thrush
context_page_description: The barred owl, also known as the northern barred owl or, more informally, hoot owl, is a large species of owl. A member of the true owl family, Strigidae, they belong to the genus Strix, which is also the origin of the family’s name under Linnaean taxonomy. Barred owls are brown to gray overall, with dark striping on the underside contrasted immediately above that with similarly-dark and tight barring about their throat and nape. Barred owls are largely native to eastern North America, but have expanded their range to the west coast of North America where they are considered invasive. Mature forests are their preferred habitat, but they can also acclimate to various gradients of open woodlands. Their diet consists mainly of small mammals, but this species is an opportunistic predator and is known to prey upon other small vertebrates such as birds, reptiles, and amphibians, as well as a variety of invertebrates.
  Barred owls are brown to gray overall, with dark striping on the underside. Barred owls have typical nesting habits for a true owl, tending to raise a relatively small brood often in a tree hollow or snag in forested areas.
context_section_description: Throughout the barred owl's range, other birds are taken as prey, although avian species make up a much smaller proportion of their diets than mammals. The maximum known representation of bird prey in a barred owl food study was 25.1% in Alberta, meaning that they augment their diet less heavily with bird prey than their near equivalent in Europe, the tawny owl. No specific variety of bird is subject to the most frequent predation by barred owls and birds are the most diverse class in these owl’s prey spectrum, with more than 100 species of bird known to be hunted. About 60% of bird species in the prey spectrum and nearly 54% of the frequency (in 7077 prey items) amongst birds known to be hunted are passerines, which are generally small, active and diurnal denizens that predominate among the species composition of the woodlands inhabited by barred owls. Medium-sized passerines in particular may be slightly preferred, with a wide array of thrushes, jays and icterids hunted. Common birds like the northern cardinal and the American robin are taken fairly regularly when opportuned upon. Smaller passerines, often around the same size as the mice and voles popular in the diet, are also regularly reported as prey. Conspicuous nesting sites of barn swallow and purple martin on manmade structures and objects were revealed via video-monitoring to suffer heavy predation by barred owls. In the case of the barn swallows, all ages of swallow as well as possibly eggs were eaten. 65 of 95 monitoring barn swallow nests were consumed by owls over a 3 year period. The muddy bank nests of cliff swallows are also vulnerable to barred owls, while other swallow species are known to be opportunistically taken. 
  In more enclosed wooded areas, radio-tagging and video-monitoring of various passerines nests as well as examinations of owl pellets has shed light on the relationship of barred owls with these potential prey resources. Not only was the barred owl found to be a surprisingly routine predator at woodland passerine nests, but that an unexpected bulk of the acts of predation in studies from Missouri and Illinois were carried out during the daytime. Many different forest bird species (most frequently acadian flycatchers and indigo buntings in Missouri and Illinois) were hunted. These studies indicated that the barred owl may snatch passerines of any age, but recent fledglings are taken preferentially due to their more conspicuous behavior and limited ability to fly away. In Minnesota, about 62% of studied hermit thrush and ovenbird fledglings were taken per one study, with all thrush that nested in the 50 m (160 ft) radius of the barred owl’s nests failing to produce any young. A similarly high rate of local determent by barred owls has been found for other woodland thrushes like the veery, wood thrush and varied thrush, with the additional finding that pre-dawn singing by certain thrushes, when their escape abilities are dulled by the dim light, leaves them vulnerable to barred owl ambushes. Forest birds seem to recognize the barred owl as a threat, with mobbing behavior evoked easily by playing recordings of their calls in the daytime.
  A wide diversity of bird prey may be occasionally hunted by barred owls in different circumstances. Smaller or mid-sized bird prey species known have including different species, though usually a relatively low species diversity and in low numbers, beyond swallows and thrushes of tyrant flycatchers, vireos, chickadees, wrens, mimids, tanagers, other cardinalids and finches. Somewhat higher diversity of species are known from the sparrow and warbler families. Birds down to the size of the calliope hummingbird, North America’s smallest hummingbird at 2.7 g (0.095 oz), may be taken by barred owls. At the opposite end of passerine prey for barred owls, this species will sometimes take all ages of the American crow, from very young nestlings to adults. Numerous non-passerine birds are also taken, though seldom in great numbers and of low known species diversity. One exceptional family is the woodpeckers, which are
caption: Studies have determined that hermit thrush cannot nest successfully in close proximity to barred owls due to their predatory pressure.
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