US Department of Agriculture, Division of Ornithology and Mammalogy. Avian predation on Purple Martins nesting in artificial housing. Nest structure and breeding habitat characteristics of Barred Owls in Manitoba, Canada. The breeding and feeding ecology of a Barred Owl Strix varia Barton population in Kings County, Nova Scotia. Master’s Thesis, Acadia Univ., Wolfville, NS. Spatial habitat selection by Barred Owls in the boreal forest of Saskatchewan, Canada.
Roost site selection may be partially dictated by thermoregulation, as in spotted owls, with shadier roosts likely to mitigate heat stress. They seldom rely on camouflage, instead often flying at the least disturbance and not allowing close approaches, making them potentially difficult to observe. Yet, on the other hand, they can be surprisingly tame and seemingly curious of people in the wild; further they are considered “as mild and engaging” as a predator can be.
The mean size of black rats taken in Oregon was 250 g (8.8 oz), indicating that here large adults of this species were selected. Beyond the typical more meadow-dwelling voles and woodland edge-dwelling native mice, larger and more forest dwelling rodents of different varieties can be of variable import. Numerous woodrat species may be taken and may provide a hearty meal to a barred owl, at a mean body mass when taken of 285 g (10.1 oz) for unidentified species. The average hatchling weighs about 46 g (1.6 oz). Like most birds, the young are initially altricial.
The bill is pale straw-yellow while the cere is “horn-colored”. Its eyes are of a blackish-brown color, this being the only true owl of the eastern United States which has brown eyes; all others have yellow eyes. The eyes may appear intensely black in the field and, although large, are fairly closely set.
John James Audubon illustrated the barred owl in Birds of America (published in London, 1827–1838) as Plate 46, where it is shown threatening a grey squirrel. The image was engraved and colored by Robert Havell’s London workshops. The original aquatint by Audubon is owned by the Brooklyn Museum. A barred owl that drowned after entanglement with fishing line. Barred owl nestlings peer out of the typical nesting site, a spacious tree hollow. The barred owl is normally nocturnally active and sleeps during the day.
The muddy bank nests of cliff swallows are also vulnerable to barred owls, while other swallow species are known to be opportunistically taken. Barred owls are opportunistic predators of the woodlands. Like the tawny owl, the barred owl usually hunts from a perch. During hunting efforts, they glide briefly from perch to perch until prey is detected.
Earthworms were most prominent in the foods of barred owls in Nova Scotia, where 27.6% of 186 video-monitored prey deliveries in Nova Scotia were worms, the most regularly delivered of all prey types there. Barred owls are thought sychophant to be partly responsible for the recent decline of the northern spotted owl, native to British Columbia, Washington, Oregon, and California. There are ecological discrepancies between the species in areas of sympatry.